These blueberry oatmeal crumble bars are bursting with juicy blueberries, and filled with crunchy oatmeal crumble. They can be made with fresh or frozen blueberries, and the oatmeal mixture doubles as the base and crumble topping. Delicious for breakfast or dessert – you’ll love this easy recipe!
Last year I made blueberry crumble bars that were a huge hit over the spring and summer months. They have a buttery shortbread base, a layer of fresh blueberries, and a crunchy crumble topping.
But I wanted to make a version with oatmeal crumble. Because I’m pretty sure that if there’s oatmeal – then it’s breakfast approved. And because adding oatmeal creates even more delicious crunchy crumble texture. And that’s always a good thing.
Enter – blueberry oatmeal crumble bars. They have a crunchy oatmeal cookie base, a layer of extra juicy blueberries, and cinnamon oatmeal crumble on top. There’s so much texture, and the oatmeal really holds up to the juicy berries.
I’ve definitely had these for breakfast (they can’t be that much worse than sugary cereals), or with a scoop of vanilla ice cream for dessert. And for whatever reason, I think they’re completely delicious cold and right from the fridge.
Blueberry Oatmeal Crumble Bar Recipe
One of the best parts of this recipe is that we’re using the same mixture for the oatmeal cookie base and the crumble topping. First, we whisk together flour, oats, sugar, and a little cinnamon. Then melted butter and 1 egg yolk are stirred in.
Make sure to use old-fashioned or large flake oats. Quick oats & instant oats have less texture and behave more like flour in recipes. So I don’t recommend the substitution in this recipe.
About 1 cup is reserved for the crumble topping, then the rest of the mixture is pressed into the bottom of the pan.
For the blueberry filling we’re using blueberries, lemon juice, a little sugar and some cornstarch. You can use fresh or frozen berries, however the bake time will be a little longer if using frozen berries.
Then spoon the the blueberry mixture is spooned on top of the bottom oatmeal layer. The leftover oatmeal mixture is crumbled on top (it’ll feel like damp sand) and we’re ready to bake.
These blueberry oatmeal crumble bars are full of texture and packed with juicy berries. I love making these for dessert and then having the leftovers for breakfast.
Here’s a quick video showing you exactly how to make these blueberry crumble bars:
For more fruit crumble bars – try these other favorites:
Or for more blueberry recipes, try these other favorites:
Blueberry Oatmeal Crumble Bars
For the Base & Crumble Topping
- 1 cup all-purpose flour
- 3/4 cup old-fashioned oats , or large flake oats (not quick oats or instant oats)
- 1/2 cup granulated sugar
- 1/4 cup packed brown sugar
- 1/2 teaspoon cinnamon
- 1/4 teaspoon salt
- 1/2 cup unsalted butter , melted
- 1 large egg yolk
- 1 tablespoon packed brown sugar
For the Blueberry Layer
- 2 cup blueberries , fresh or frozen - see baking time adjustment if using frozen
- 2 tablespoons lemon juice , freshly squeezed (use 1 tablespoon if using frozen berries)
- 1/4 cup granulated sugar
- 2 teaspoons cornstarch
- Preheat the oven to 350F degrees. Line an 8x8 baking pan with aluminium foil and grease with non-stick cooking spray.
- In a medium bowl whisk together the flour, oatmeal, granulated sugar, 1/4 cup brown sugar, cinnamon, and salt. Gently stir in the melted butter & egg yolk.
- Remove 1 cup of the mixture.
- Press the remaining mixture into the bottom of the prepared pan.
- In a medium bowl mix together all the ingredients for the blueberry layer. Spoon over top of the base oatmeal cookie mixture in the pan.
- To the reserved 1 cup of oatmeal mixture, stir in the 1 additional tablespoon of brown sugar. Crumble the mixture over top of the blueberry layer. I like to form big crumbles by squeezing it in my fist.
- Bake in the preheated oven for about 40-45 minutes or until you see the blueberries bubbling and the top crumble turning golden brown. If you used frozen berries, the bake time will be 50-55 minutes.
- Allow to cool fully to room temperature (at least 3 hours) before cutting into the bars. Bars are easiest to cut when they're cold using a sharp knife.