→ Base Layer
01 - 2 cups all-purpose flour
02 - 1/2 cup granulated sugar
03 - 1/2 teaspoon baking powder
04 - 1/4 teaspoon salt
05 - 1/2 cup unsalted butter, cold and cubed
06 - 1 large egg, lightly beaten
→ Apple Filling
07 - 3 medium apples, peeled, cored, and diced
08 - 1/4 cup granulated sugar
09 - 1 teaspoon ground cinnamon
10 - 1 tablespoon lemon juice
11 - 1 tablespoon all-purpose flour
→ Crumble Topping
12 - 3/4 cup old-fashioned oats
13 - 1/2 cup all-purpose flour
14 - 1/3 cup brown sugar, packed
15 - 1/4 teaspoon ground cinnamon
16 - 1/4 teaspoon salt
17 - 1/2 cup unsalted butter, melted