These delicious Bluebarb Crumble Slices are buttery sweet shortbreads with a layer of blueberry rhubarb jam squashed in between. To prepare them, make a simple crumbly, biscuity mixture. Sandwich together, then bake, let them rest, then enjoy the sweetest summer flavors in every decadent bite.

Bluebarb Crumble Slices

Easy Bluebarb Crumble Slices

BySharon
2 Comments
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The good news is this delicious Bluebarb Crumble Slices recipe is vegetarian, nut-free, and egg-free. With some substitutions, it could also be gluten-free and dairy-free.

These decadent crumbles aka blueberry slices are a perfect blend of fruity goodness and buttery, crumbly perfection and are sure to become a favorite in your repertoire of sweet treats. They can be enjoyed cold, taken straight from the fridge, at room temperature, or warmed up slightly.

When we were kids, these treats were a regular bake; we couldn’t wait for the next batch. So, whether you’re simply treating yourself, which you do all the time, or hosting a special brunch for friends, you can be sure no one will forget these delicious, fruity, crumbly perfections.

What’s To Love?

💕 Quick and easy to prepare.
💕 The sweetness of the blueberries complements the tartness of the rhubarb, resulting in a deliciously unique taste.
💕 The crumble topping adds a crunchy contrast to the soft and juicy fruit filling. This combination of textures makes each bite exciting and satisfying.
💕 Offer a deep, satisfying, jammy, crumbly taste.
💕 There’s something inherently comforting about a crumble that takes coziness to another level.
💕 Is a surefire crowd-pleaser that will have everyone coming back for seconds.
💕 Both blueberries and rhubarb are often available fresh in the spring and summer, making this dessert a seasonal favorite. However, it can also be made year-round with frozen fruit.
💕 Perfect for entertaining to serve at parties or gatherings.

Have you already tried these Bluebarb Crumble Slices? If so, let us know how it was…we can’t wait to hear all about it!

Let’s Talk Ingredients

We feel every ingredient adds to the overall taste and texture; if you remove one, it’s like you’ve removed them all.

  • Butter — for the best results, use dairy butter at room temperature.
  • Flour — use all-purpose flour, which is sometimes referred to as plain flour.
  • Vanilla Extract — use Nielsen Massey, which is made with real vanilla beans and alcohol. The vanilla is quite potent and adds a beautiful richness to desserts.
  • Salt — use Himalayan salt; it brings out the flavor and offsets the sweetness.
  • Tapioca Flour — adds a beautiful sheen without making the jam cloudy and helps the jam set when heated.
  • Jam — for this recipe, we suggest making our blueberry rhubarb jam.
  • Oats — use rolled oats; they add a crumbly appearance and a better texture.
  • Powdered Sugar — also called icing sugar in some countries.
  • Regular Sugar — we prefer caster sugar as opposed to granulated because it incorporates better.
  • Light Brown Sugar — or use coconut sugar.
  • Cinnamon — use ground Ceylon cinnamon because its flavor is sweet and has a beautiful, fresh aroma and exquisite taste.

For more detailed ingredients, see the recipe card.

Customizations

Here are some foodie alternatives should you want to make some changes:

  • Butter — a great alternative is dairy-free butter.
  • Flour — rice flour is a great alternative; substitute equal amounts of rice flour and 1/2 teaspoon of guar gum.
  • Vanilla Extract — if you prefer a non-alcohol base, use vanilla flavoring.
  • Tapioca Flour — cornflour can be used but will make the jam cloudy.
  • Oats — gluten-free oats can be used; substitute equal amounts.
  • Jam — feel free to use a store-bought mix of blueberry jam and rhubarb jam. Both these jams weigh 340g, for a total of 680g. If you don’t mind a little less jam than the recipe suggests, then you do not need to buy extra jars.

Looking for something slightly different? check out our recipe card for some tempting variations.

When substituting ingredients, it’s essential to remember that the taste, texture, and overall result of the slices might differ, particularly if you’re substituting many ingredients.

If you have made the Bluebarb Slices with any customizations, we’d love to hear about it; please message us in the comments.

Instructions – Overview

Bluebarb Crumble Slices are easy to make and are even easier to eat. Here’s a breakdown of how to get started on your baking journey (more detailed instructions are in the recipe card):

Bluebarb Crumble Slices instructions

▶︎ The shortbread base is combined with butter, flour, sugar, salt and vanilla. It’s then pressed into the bottom of the prepared baking pan to form an even crust and baked.

▶︎ The filling bursts with the blueberries and rhubarb’s natural sweetness, enhanced with a sprinkle of tapioca to create a shiny appearance. The center is a masterpiece of lovely, sweet, plummy flavors.

▶︎ The topping is combined with flour, rolled oats, sugar, butter, and cinnamon and then rubbed together to create a fine crumble. Once crumbly, it’s sprinkled over the jammy mixture and baked again.

▶︎ The contrast of crunchy and tender creates a harmonious, comforting, and satisfying balance in every bite.

▶︎ When removed from the oven let it cool slightly before serving with a scoop of Vanilla Ice Cream or a dollop of Whipped Cream.

For more detailed instructions, notes, and ideas…see the recipe card.

Removing From The Pan

For best results, use a cake pan with a detachable base (unclippable sides), like this square baking pan.

Warm a knife under hot water and pat it dry. Before taking the bluebarb slices out of the pan, run the knife around the edges. Unclip the springform sides, lift the pan off, and gently slide the loose pan bottom onto a plate. If you lined your pan with parchment paper, remove it now. Cut into squares and serve.

Tools You’ll Need

Want to make the best Bluebarb Slices? Using the correct equipment for preparation is essential; we think they’re a big helping hand. We understand that you might already have some of these kitchen tools to make this recipe, or you might want to use other tools and may not require our recommendations. Here are some of our suggestions to get you started:

If you love those gadgets for this recipe, then you’ll love this food processor for mixing, chopping, grating, whisking, beating, and more. It would definitely make making the Bluebarb Crumble Slices easier, as you can crumble the topping without having to do it by hand. It’s our go-to for many of our recipes, and we think every budding chef needs it.

Amazon - food processor

Magimix Food Processor — we’ve owned the 5200 XL for over 30 years, and it’s still going strong. It has BPA-free bowls, the motor is quiet, and it is built to last. We believe the 4200 XL is the better option as it’s a middle-ground size to work with. All sizes offer an unbeatable 30-year motor and 3-year parts guarantee.

Check out our favorite kitchen equipment that we love to use with all our recipes.

Storing

See our FAQs for detailed instructions on storing, refrigeration, freezing, and defrosting and for answers to readers’ questions.

Do you have a question? If so, let us know in the comments and we’ll reply within 24-48 hours and add your question to our FAQs if relevant.

Pairing

Bluebarb Crumble Slices are frequently eaten as a standalone dessert, but they can easily be paired. Here are some suggestions and our favorite go-to’s what to eat with them:

▶︎ They can be served cold or hot, with a dollop of freshly Whipped Cream or Vanilla Ice Cream.

▶︎ When served warm, a drizzle of Thick Custard brings on the British tradition. We often serve them with custard; it’s one of our favorite go-tos.

▶︎ For a dairy-free and gut-friendly option, try our Vanilla Coconut Yogurt.

More Recipes

Here are some other delicious recipes that we think you might also like:

Thank you for checking out Blubarb Crumble Slices!

We hope you enjoy making and eating it! Let us know how you get along, and please rate using the ⭐️ by the comments. HUNGRY FOR MORE? Subscribe to our newsletter and follow us on Facebook, YouTube, and Pinterest for all of our latest updates. Happy Baking!

⭐️ Quick Tip: Read the recipe in its entirety before you start. This will help you understand the ingredients, steps, and timing involved, and allow you to prepare any necessary equipment or ingredients beforehand. Voila…you’re all set to go!

Bluebarb Crumble Slices

Blubarb Crumble Slices

384kcal
5 from 1 vote
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Prep 15 minutes
Cook 40 minutes
Resting Time 30 minutes
Total 1 hour 25 minutes
These delicious Bluebarb Crumble Slices are buttery sweet shortbreads with a layer of blueberry rhubarb jam squashed in between. To prepare them, make a simple crumbly, biscuity mixture. Sandwich together, then bake, let them rest, then enjoy the sweetest summer flavors in every decadent bite.
Servings 12
Course Desserts
Cuisine American/British

Ingredients

Shortbread Base
Filling
Crumble Topping

Equipment

Method

Preparation
  1. Preheat your oven to Gas 4, 180°C, 350°F.
  2. Grease and line the baking pan with unbleached parchment paper.
Shortbread Base
  1. Combine the flour, cold cubed butter, sugars, vanilla, and salt in a food processor.
    230 grams Butter, 260 grams All-Purpose Flour, 30 grams Powdered Sugar, 50 grams Golden Caster Sugar, 2 tsp Vanilla Extract, pinch Himalayan Salt
  2. Pulse until the mixture resembles breadcrumbs.
  3. Press the mixture into the bottom of the prepared baking pan to form an even crust.
  4. Bake for 15 minutes or until lightly golden.
Filling
  1. Remove the jam from the jars and add to a clean bowl.
    Note:Feel free to use store-bought jam such as this blueberry jam and this rhubarb jam, or better still make our blueberry rhubarb jam.
    800 grams Blueberry Rhubarb Jam
  2. Heat in the microwave for 30 seconds on high.
  3. Add the tapioca flour.
    2 tbsp Tapioca Flour
  4. Mix well.
  5. Add to the lightly cooked base.
Crumble Topping
  1. In a clean bowl, combine the oats, flour, soft butter, brown sugar, and ground cinnamon.
    100 g Rolled Oats, 100 g All-Purpose Flour, 80 g Butter, 80 g Light Brown Sugar, ½ tsp Ground Ceylon Cinnamon
  2. Mix using your fingers until the ingredients come together in a crumbly texture.
  3. Sprinkle the crumble topping over the jammy mixture, covering it evenly or dotting it around.
Baking
  1. Bake in the preheated oven for 25 minutes or until the topping is golden brown, and the fruit filling is bubbling.
  2. Allow the Bluebarb Crumble Slices to cool in the pan for at least 30 minutes before transferring to a wire rack to cool completely.
  3. Once cooled, slice into squares or rectangles.
  4. Sieve powdered sugar over the top (optional) before serving!

Nutrition

Calories384kcalCarbohydrates43gProtein4gFat22gSaturated Fat13gPolyunsaturated Fat1gMonounsaturated Fat6gTrans Fat1gCholesterol56mgSodium6mgPotassium79mgFiber2gSugar13gVitamin A646IUVitamin C0.003mgCalcium22mgIron2mg

Notes

Here are some top tips to help you succeed in making Bluebarb Slices slices like a pro:
  1. Use fresh, high-quality blueberries and rhubarb for the best flavor and texture. Out-of-season berries give quite a bitter aftertaste.
  2. When making the shortbread crust, ensure that the butter is cold. Cold butter helps create a flaky and tender crust. If needed, cut the butter into small cubes and place it in the freezer for a few minutes.
  3. To achieve the ideal crumble texture, use softened butter and mix the ingredients until they resemble coarse crumbs. This topping adds a delightful crunch, so ensure it’s evenly distributed over the fruit filling.
  4. Press the shortbread mixture firmly and evenly into the baking pan to create a solid base for the bluebarb slices. This ensures that each bite has a perfect balance of crust and filling.
  5. The topping indicates doneness when it’s turned slightly golden.
  6. Keep a close eye on the slices as they bake. The topping should be golden brown, and the fruit filling should be bubbling. Overbaking may result in a dry texture, so check for doneness around the 25-minute mark.
  7. Allowing the slices to cool in the pan for at least 30 minutes before slicing them ensures the filling is set, and makes it easier to cut neat slices without the filling oozing out.
  8. Feel free to use store-bought jams, such as blueberry jam and rhubarb jam. Both these jams weigh 340 grams; if you don’t mind a little less jam, then you do not need to buy extra jars. This would reduce the cost by not having to buy two jars of each flavor.
  9. Try our Apple Plum Jam. Create a double batch, then use half to store in jars and the other half for the Bluebarb Slices.
  10. Jams, such as blueberry, loganberry, acai berry, and redcurrants, can be used to experiment with different flavors. If you choose berries such as strawberries, blackberries, or pomegranates with seeds, you may want to consider their size.
  11. Dairy-Free: Use dairy-free butter.
  12. Gluten-Free: Use brown rice flour and 1/2 teaspoon of guar gum, and use gluten-free oats.

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FAQ’s & Troubleshooting

By addressing these FAQs and troubleshooting tips, you can overcome common challenges and create a delicious batch of Bluebarb Crumble Slices every time.

Store leftovers in an airtight container at room temperature for the first day. After that, it’s best to refrigerate them to maintain freshness. Reheat briefly in the oven for that freshly baked taste. Use within four days of making.

Yes, you can freeze the Bluebarb slices. Wrap in plastic wrap or foil to prevent freezer burn and place in airtight containers. The slices can be frozen for up to 3 months.

Store in the refrigerator in the original container for 2-3 hours or overnight before serving.

You can use frozen fruits, but remember that they may release more moisture during baking. Thaw and drain excess liquid from the fruits before using them to prevent the filling from becoming too watery.

The topping should be slightly golden brown, and the fruit filling should be bubbling. Stick a toothpick into the center; it should come out with moist crumbs, not wet batter.

We do not suggest using oil instead of butter because it will deflect the shortbread texture.

Allow the blueberry rhubarb slices to cool in the pan for 30 minutes before transferring them to a plate. This will prevent the slices from breaking or sticking to the pans.

If the mixture seems too dry when mixing, add a tablespoon of melted butter at a time until it holds together better.

Be cautious not to over-bake, which may result in a dry texture.

Adjust the texture by adding more softened butter. Add one tablespoon at a time until the mixture becomes crumbly and easy to sprinkle over the filling.

If using frozen fruits, make sure to drain excess liquid after thawing. The runniness of the filling depends on the quality of the jam used; you can mix in another tablespoon of tapioca or cornstarch to the jam mixture to help thicken the filling.

Cover the pan with aluminum foil halfway through baking to prevent the topping from over-browning while the fruit filling finishes cooking. If you do this, the Bluebarb Crumble Slices may need five more minutes in the oven.

Your Questions Matter

Do you have a question? If so, let us know in the comments and we’ll reply within 24-48 hours and add your question to our FAQs if relevant. If you don’t already follow us, head over to our Twitter or Facebook to keep up to date with all our new recipes and articles.

For food safety top tips, check out USDA.gov.

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Hey, I’m Sharon, I’m a full-time food blogger, mother of 3 grown adults and 3 huskies. Most days you can find me in the kitchen creating new recipes, I love cooking indulgent bakes and love sharing them. I am lucky to connect with and inspire people from all around the world and help you on your cooking journey so you can eat in style!

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2 Comments

  1. 5 stars
    I made this yesterday, and wow it’s such an amazing crumble. The combo of flavors is dino! Such a fun dessert to make and the kids joined in too.

    Reply
5 from 1 vote

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