Blueberry Crumble Bars

Ingredients:
- 2 cups all-purpose flour
- 1 cup granulated sugar
- 1/2 teaspoon baking powder
- 1/4 teaspoon salt
- 1/2 cup unsalted butter, cold and cut into small pieces
- 1 large egg
- 1 teaspoon vanilla extract
- 2 cups fresh or frozen blueberries
- 1/4 cup granulated sugar
- 2 tablespoons cornstarch
- 1 tablespoon lemon juice

Instructions:
1. Preheat your oven to 375°F (190°C) and line a 9x9-inch baking pan with parchment paper.
2. In a large mixing bowl, whisk together the flour, 1 cup sugar, baking powder, and salt.
3. Add the cold butter pieces to the flour mixture and use a pastry cutter or your fingers to cut it into the mixture until it resembles coarse crumbs.
4. In a separate small bowl, beat the egg and vanilla extract together. Add the mixture to the flour mixture and stir until the dough comes together.
5. Press two-thirds of the dough into the prepared baking pan to form a crust layer.
6. In another bowl, mix together the blueberries, 1/4 cup sugar, cornstarch, and lemon juice until well-coated.
7. Evenly spread the blueberry mixture over the crust layer in the baking pan.
8. Crumble the remaining dough over the top of the blueberries.
9. Bake in the preheated oven for about 40-45 minutes, or until the top is golden brown and the blueberries are bubbling.
10. Allow the bars to cool completely in the pan before cutting into squares. Enjoy!

Note: You can substitute the blueberries with any other fruits like raspberries or strawberries if desired.