Dessert, Everyday Eats, Recipes, Summer

Vegan Mixed Berry Crumble Bars

Fresh, vibrant, and delicious – these Vegan Mixed Berry Crumble Bars taste like summer in every bite! A simple oat base topped with mixed berries and an oat crumble topping.

Is there anything better than a summer dessert? With some many great produce in season, they’re always so fresh and flavourful. These Vegan Mixed Berry Crumble Bars are no exception! Loaded with fruit, we used frozen but you can also use fresh, and completed with an oat crumble crust and topping. Perfect for snacking or a sweet treat, take these goodies on your next picnic, or hike or enjoy them in your own backyard.

Coming together with just 12 simple ingredients and active prep time of only 15 minutes, this is the summer dessert you need! It’s both sweet and tart with a hearty, yet fresh bite. We promise you’ll be making this vegan dessert ALL SUMMER LONG.

Why you’ll love this recipe:

  • Packed with flavourful summer fruit!
  • Super simple to make with just 12 ingredients.
  • Perfect for a sweet summer dessert.
  • Great for picnics and potlucks!

Top tips for making Mixed Berry Crumble Bars:

  • Leave some parchment overhanging. For easy lifting and removal, we like to line our pan with parchment paper and leave some overhanging the edges. The excess acts as little paper handles you can use to lift the crumble bars out of the pan.
  • Adjust the recipe slightly depending on fruit. We made this recipe using a mixed berry frozen fruit blend, but you can use fresh if you prefer. You may just need to add an extra tablespoon of lemon juice so that you have enough liquid in the berry layer. See ingredient notes.
  • Really pack down the base. For the best structural integrity (since it’s a fairly weighty dessert) be sure you really pack down the crumble base. We like to use the back of a measuring cup to press it down and into the corners and edges.
  • Allow to cool before slicing. This recipes NEEDS to cool before you slice into squares or bars. The cooling is what helps the berry layer solidify so you don’t have a soupy mess.

Ingredient Notes:

  • All-Purpose Flour – We use all-purpose flour (we like to use the No Name All-Purpose Flour) for most of our recipes and typically don’t test with anything else. You can try using a different flour, but know that depending on the flour choice it could drastically change the results of the recipe.
  • Old-Fashioned Oats – We like the Bob’s Red Mill brand but you can most likely use any brand you want for this recipe.
  • Sugars – We don’t recommend altering this too much or at all. This combination of sugars creates the perfect level of sweetness and the correct texture!
  • Vegan Butter – We use Becel Plant Based Sticks as our vegan butter.
  • Flax Egg – Don’t skip this as it helps hold it all together. If you prefer you can also use a chia egg or vegan egg replacer.
  • Mixed Berries – We used a frozen mixed berry blend but you can use fresh if you want. Just keep in mind that frozen typically has more moisture so you may need to increase the amount of lemon juice in the recipe.
  • Lemon Juice – Perfectly balances the sweet flavour from the berries and sugar. Plus it adds a fresh bite! You can substitute this with any citrus juice of your preference.
  • Cornstarch – This is used to get the correct texture for the berry layer, we wouldn’t recommend substituting this ingredient as we haven’t tested it with anything else.
  • Chia Seeds – Creates a great texture for you berry filling. If you’d rather leave this out, we’d recommend adding an extra tablespoon of cornstarch to the recipe.

Recipe FAQ:

Can I use fruit other than berries?

We have only tested this recipe with berries so we couldn’t say if it would work for sure. Other fruit we *think* you could use in this recipe include: peaches, nectarines, plums, and apricots. Just remember that all fruit has different moisture levels so you may need to adjust the cornstarch and lemon juice if you are swapping fruit.

How do you properly store Mixed Berry Crumble Bars?

We recommend storing them in an air-tight container for up to 4 days. If you don’t think you can eat all the bars before they go bad, we recommend freezing them for later.

Other vegan desserts you’ll love:

How to make Vegan Mixed Berry Crumble Bars:

Vegan Mixed Berry Crumble Bars

Fresh, vibrant, and delicious – these Vegan Mixed Berry Crumble Bars taste like summer in every bite! A simple oat base topped with mixed berries and an oat crumble topping.
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Course: Dessert
Cuisine: American
Prep Time: 15 minutes
Cook Time: 50 minutes
Total Time: 1 hour 5 minutes
Servings: 9 bars


Oatmeal Base & Topping

  • 240 g (2 cups) all-purpose flour
  • 4 g (1 tsp) cinnamon
  • 144 g (1 ½ cups) old-fashioned oats
  • 100 g (½ cup) white sugar
  • 100 g (½ cup) brown sugar
  • 226 g (1 cup) vegan butter melted
  • 1 flax egg, (1 tbsp ground flaxseed + 3 tbsp water)

Berry Layer

  • 450 g (3 ½ cups) frozen mixed berries
  • 50 g (¼ cup) granulated sugar
  • 30 mL (2 tbsp) lemon juice
  • 40 g (4 tbsp) cornstarch
  • 26 g (2 tbsp) chia seeds


  • Preheat the oven to 350°F degrees.
  • Line a 9×9 inch pan with parchment paper leaving an overhang around all the edges. Set aside.
  • Add all-purpose flour, cinnamon, rolled oats, and both sugars to a large bowl and mix to combine. Stir in the melted butter and flax egg – the mixture should look like wet sand.
  • Reserve about 2/5 of the oat mixture for the topping, then press the rest into the bottom of the prepared pan. Use the bottom of a measuring cup to press it as firmly as you can. Set aside.
  • Toss together the mixed berries, granulated sugar, lemon juice, chia seeds, and cornstarch in a large bowl. All the berries should be evenly coated.
  • Spoon the berry mixture over top of the base, don't worry if it seems thick, as it cooks it will compress into a jam-y layer.
  • Crumble the remaining oat mixture over top and pressing gently on top of the berry mixture. It's okay if the topping doesn't completely cover the berries, you want some peeking through!
  • Bake in the preheated oven for 45-50 minutes, or until the top is golden brown and the berry mixture is bubbling.
  • Cool the pan on a wire rack for 30 minutes. Then remove baked bars from the pan and transfer to the fridge to cool completely.
  • Once it's completely cooled, slice into 9 or 16 squares. Store in an airtight container for up to 4 days.


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