Mixed Berry Crisp

Preheat the oven to 425 degrees F (220 degrees C). Grease a 9x13-inch baking dish.

Mix together berries, 1/4 cup white sugar, 1/4 cup brown sugar, cornstarch, lemon juice, and 1/2 teaspoon ground cinnamon for the filling in a bowl until well combined. Pour into a separate, ungreased baking dish.

Bake filling in the preheated oven until berries are hot, about 10 minutes.

While berries are baking, mix together flour, 1/4 cup white sugar, 1/4 cup brown sugar, baking powder, and salt for the crust in a bowl. Cut in 1/2 cup cold butter with a pastry blender until crumbly. Spread crust mixture into the bottom of the prepared 9x13-inch baking dish and pour hot berry filling on top.

Mix together oats, 1 cup flour, 1 cup brown sugar, and 1 teaspoon ground cinnamon for the topping in a bowl. Cut in 1 1/2 cups cold butter with a pastry blender until crumbly. Sprinkle topping over the berry filling.

Bake in the preheated oven until filling is bubbling and topping is golden brown, about 35 minutes.