- Cooking spray
- 4 teaspoons cornstarch, divided
- 2 tablespoons brown sugar
- 1/2 teaspoon vanilla extract
- 1 pound fresh or frozen blueberries
- 2 1/4 ounces all-purpose flour (about 1/2 cup)
- 1/2 cup packed brown sugar
- 1/4 cup old-fashioned rolled oats
- 3 tablespoons chopped walnuts
- 2 tablespoons cornmeal
- 1/2 teaspoon salt
- 1/4 teaspoon ground cinnamon
- 1/4 cup chilled butter, cut into small pieces
1. Preheat oven to 375°.
2. Coat an 8-inch square glass or ceramic baking dish with cooking spray. Sprinkle 2 teaspoons cornstarch evenly in dish.
3. Combine remaining 2 teaspoons cornstarch, 2 tablespoons brown sugar, vanilla, and blueberries in a large bowl; toss. Place in prepared baking dish.
4. Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and next 6 ingredients (through cinnamon) in the bowl of a food processor; pulse twice to combine. Add butter; pulse 5 times or until the mixture resembles coarse meal. Spoon topping evenly over blueberries, packing down lightly. Bake at 375° for 30 minutes or until filling is bubbly and topping is golden.