- Crust:
- 3 cups all-purpose flour
- 1 cup unsalted butter
- 3/4 cup white sugar
- 1 egg
- 1 teaspoon baking powder
- 1/2 teaspoon salt
- Apple Filling:
- 3 tablespoons unsalted butter
- 5 Granny Smith apples, peeled and diced
- 1/2 cup brown sugar
- 1/2 cup white sugar
- 2 teaspoons ground cinnamon
- 1/4 teaspoon grated nutmeg
- 1 pinch salt
- 1 tablespoon cornstarch, or as needed
- Preheat oven to 350 degrees F (175 degrees C). Line a 9×13-inch baking pan with parchment paper.
- Combine flour, 1 cup butter, 3/4 cup white sugar, egg, baking powder, and 1/2 teaspoon salt in a food processor; pulse until crumbled and easily formed into dough when pinched. Pour 3/4 of the dough into the prepared pan; press down with your hands until crust is even and well packed.
- Melt 3 tablespoons butter in a skillet over medium heat. Add apples, brown sugar, 1/2 cup white sugar, cinnamon, nutmeg, and salt; cook and stir until apples are softened, about 5 minutes. Stir in cornstarch; mix, adding more cornstarch if needed, until liquids are thickened.
- Pour apple mixture onto crust; smooth with a spatula until even. Crumble remaining dough on top.
- Bake in the preheated oven until crumbles on top are lightly brown, 30 to 40 minutes. Let cool for 10 minutes; cut into bars.