This Blueberry Crumble, also known as Crisp, is the one dessert I can simply never get enough of. Fresh blueberries are mixed with a squeeze of lemon juice and cornstarch, with no added sugar so their natural sweet and tart flavor can shine. They're topped with a simple crumble made with flour, rolled oats, sugar and melted butter - no cold butter, no rubbing! Once baked, this crumble has the perfect ratio of jammy blueberries to crispy, buttery topping. It requires only 5 minutes of easy work, and is unbelievably warm and comforting - whether eaten on its own or with vanilla ice cream.
3 quick steps
This recipe needs only 3 quick steps that take 5 minutes of work before the crumble is ready to go in the oven:
- Toss the blueberries with cornstarch, lemon juice and a pinch of salt. There's no need to add sugar here as we want the natural sweet and tart flavor of the blueberries to come through. I like to do this step directly in my baking dish to reduce the number of dirty dishes
- Make the crumble with melted butter. Simply mix together the flour, rolled oats, sugar, salt and cinnamon with melted butter and you're good to go!
- Assemble. Now add the crumble mixture on top of the blueberries - I recommend placing it in chunks using your hands, and letting some blueberries peek through
That's it! Now you're ready to bake.
Why melted butter works in this recipe
The technically "correct" way of making a crumble is to rub cold butter into dry ingredients. This is to ensure the butter stays in chunks so you end up with a craggly, crispy texture. However, after a bit of experimentation, I've found melted butter can give you the same results while cutting the work significantly. You just need to remember 2 things:
- Don't overmix. Use a light hand to mix the crumble ingredients until they just come together. Any further handling will start to develop gluten, which we don't want
- Disperse unevenly. When adding the crumble mixture on top of your blueberries, use your fingers to break it into little, uneven chunks. A rough look is best here, as that creates more surface area, and more surface area = crispier crumble!
Step by step photos
Let's quickly go over the steps with photos to help you visualize everything:
Bake until the crumble is golden and crispy and the blueberries are jammy and bubbly. Serve warm with an optional scoop of vanilla ice cream, and enjoy!
Try it with other fruits, too!
The beauty of this crumble is that the recipe works with so many different types of fruit! You can add in other berries, just like I do in my Mixed Berry Crisp, or even finely chopped apples or peaches. You can also turn it into an Easy Peach Crumble when peaches are in season.
Blueberry Crumble With Oats Recipe (Melted Butter!)
- Total Time: 50 minutes
- Yield: 8 servings
Description
Jammy blueberries (no added sugar) topped with a crispy oat topping made with melted butter. Only 5 minutes of work needed!
Ingredients
Blueberry filling:
- 4 cups of fresh blueberries, washed and dried (~650g) - can be swapped with frozen; see notes
- 2 tbsp cornstarch
- 1 tbsp lemon juice
- Small pinch of salt
Oat crumble topping:
- ⅔ cup flour (86g)
- ⅔ cup old-fashioned rolled oats (80g)
- ½ cup granulated sugar (100g)
- ½ teaspoon cinnamon, optional
- ½ tsp salt
- ½ cup unsalted butter, melted (113g)
Instructions
- Preheat your oven to 375F and lightly brush a 9" pie dish with butter
- Add the washed and dried blueberries, cornstarch, lemon juice and salt directly to the pie dish. Toss with a spoon or your hands to combine
- Add all the ingredients for the crumble topping to a bowl. Use a large spoon and gently mix until the ingredients are just combined. The result should be a thick, crumbly mixture slightly softer than pie dough. Do not over-mix
- Use your fingers to disperse the crumble topping on top of the blueberries, placing it in chunks of varying sizes. Keeping the crumble layer uneven helps ensure it is very crispy after baking. Let some blueberries peek through!
- Bake for 40-45 minutes, until the crumble is golden and crispy, and the blueberries are jammy and bubbly
- Serve warm on its own or with vanilla ice cream. You can also use plain whipped cream if you want the texture contrast without added sweetness
Notes
- Fresh vs frozen blueberries: You can easily swap the fresh blueberries with frozen. Just make sure the blueberries are fully frozen when you toss them with the other ingredients (don't let them thaw first)
- Rolled vs instant oats: I recommend 0ld fashioned rolls oats for the best texture, but if you only have instant oats, you can use them, too
- Baking dish: I recommend baking this crumble in a 9" ceramic / glass pie dish. This ensures both layers have the ideal thickness, and the ceramic heats up more slowly than metal, allowing the blueberries to become jammy. However, you may use any ceramic/glass dish of comparable size
- Make ahead and storage: You can assemble this blueberry crumble ahead of time and keep it covered in the fridge for 1 day (any longer and you risk the berries turning moldy). After baking, keep it at room temperature for up to 1 day, or in the fridge for up to 3 days. Reheat in the microwave to serve.
- Prep Time: 5 minutes
- Cook Time: 40 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
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