Filling:
Preheat oven to 350°F (175°C). Lightly grease an 8×8 baking pan.
In a large bowl, gently stir together all filling ingredients until well mixed. Transfer the mixture to the prepared baking pan.
Topping:
In a medium bowl, combine sugar, flour, baking powder, and salt. Add the vanilla extract and melted butter. Stir until fully combined. The mixture should resemble a cross between a crumb topping and a sugar cookie dough.
Using your fingers, press pieces of the topping together to form flat, irregularly shaped pieces. Distribute the topping evenly over the blackberries in the pan.
Baking:
Bake in the preheated oven for 30-35 minutes, until the berries are bubbling and the topping is beginning to turn light golden brown.
Remove from the oven and place the pan on a wire rack to cool for about 15 minutes. This cooling period will allow the juices to thicken up slightly.
Serving:
Serve the blackberry crumble warm, topped with a scoop of vanilla ice cream.
Enjoy this delicious and comforting dessert, perfect for any occasion!
