Ingredients
Scale
For the Blueberry Filling:
- 6 cups fresh or frozen blueberries (about 2 pounds)
- ½ cup granulated sugar
- 3 tablespoons cornstarch
- 2 tablespoons fresh lemon juice
- 1 teaspoon lemon zest
- 1 teaspoon vanilla extract
- Pinch of salt
For the Crumble Topping:
- 1 cup all-purpose flour
- 1 cup old-fashioned rolled oats
- ¾ cup packed light brown sugar
- ½ teaspoon ground cinnamon (optional)
- ½ teaspoon salt
- ½ cup (1 stick) cold unsalted butter, cut into small cubes
Instructions
- Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish with butter or cooking spray, or line it with parchment paper for easy cleanup.
- Prepare the blueberry filling: In a large mixing bowl, combine the blueberries, granulated sugar, cornstarch, lemon juice, lemon zest, vanilla extract, and a pinch of salt. Gently toss everything together until the blueberries are evenly coated with the sugar mixture. Let this sit for about 5 minutes while you prepare the topping—the sugar will start drawing out the juices from the berries.
- Make the crumble topping: In a medium bowl, whisk together the flour, oats, brown sugar, cinnamon (if using), and salt until well combined.
- Cut in the butter: Add the cold butter cubes to the flour mixture. Using a pastry cutter, two forks, or your fingertips, work the butter into the dry ingredients until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining. You want a crumbly, sandy texture with visible butter pieces—this is what creates those delicious crispy clusters. Don’t overmix or the butter will warm up too much.
- Assemble the crumble: Pour the blueberry mixture into your prepared baking dish, spreading it out evenly. Sprinkle the crumble topping evenly over the blueberries, making sure to cover the entire surface. You can create some larger clumps with your hands if you want extra-crispy clusters.
- Bake: Place the baking dish on a rimmed baking sheet (to catch any drips) and bake for 40-45 minutes, or until the topping is golden brown and the blueberry filling is bubbling around the edges. If the topping is browning too quickly, loosely tent the dish with aluminum foil for the last 10-15 minutes of baking.
- Cool and serve: Remove from the oven and let the crumble cool for at least 15-20 minutes before serving. This allows the filling to thicken up properly. Serve warm or at room temperature with vanilla ice cream, whipped cream, or a drizzle of heavy cream.
Notes
- Using Frozen Blueberries: No need to thaw frozen blueberries—use them straight from the freezer. You may need to add 5-10 extra minutes to the baking time.
- Adjusting Sweetness: Taste your blueberries before making the filling. If they’re very tart, you might want to add an extra tablespoon or two of sugar to the filling.
- Make It Extra Crispy: For an even crunchier topping, add ¼ cup of chopped pecans or sliced almonds to the crumble mixture.
- Prevent Soggy Bottom: Make sure your blueberry mixture sits for a few minutes before baking so the cornstarch can start working. Don’t skip this step!
- Prep Time: 15 minutes
- Cook Time: 40-45 minutes
- Category: Desert
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
Nutrition
- Serving Size: 1 piece (based on 10 servings)
- Calories: 285
- Sugar: 32g
- Sodium: 180mg
- Fat: 10g
- Saturated Fat: 6g
- Unsaturated Fat: 3g
- Trans Fat: 0g
- Carbohydrates: 48g
- Fiber: 3g
- Protein: 3g
- Cholesterol: 25mg