01 -
Preheat the oven to 350°F (175°C). Grease and flour a 9x9-inch square baking pan or line with parchment paper.
02 -
In a large mixing bowl, cream the softened butter and granulated sugar together using an electric mixer or whisk until light and fluffy, about 2 to 3 minutes.
03 -
Beat in the eggs one at a time, then add the vanilla extract. Mix until fully incorporated.
04 -
In a separate bowl, whisk together the all-purpose flour, baking powder, and salt. Gradually add the dry mixture to the wet ingredients, mixing just until combined.
05 -
Gently fold the diced apples into the batter with a spatula. Spread the batter evenly into the prepared baking pan.
06 -
In a medium bowl, combine flour, ground cinnamon, salt, granulated sugar, and brown sugar. Add the cold, cubed butter and mix using a pastry cutter or fingers until the mixture forms coarse crumbs with pea-sized butter pieces.
07 -
Sprinkle the crumb topping evenly over the cake batter. Bake for 30 to 45 minutes, or until a toothpick inserted into the center comes out clean and the crumb topping is golden brown.
08 -
While the cake bakes, melt butter in a small saucepan over medium heat. Stir in brown sugar, ground cinnamon, milk, and a pinch of salt. Cook for 2 to 3 minutes, stirring occasionally, until the mixture is smooth and the sugar has dissolved.
09 -
Allow the cake to cool for at least 15 minutes. Drizzle the warm cinnamon apple glaze over the cake before serving.