To prepare the streusel crust, mix the flour, sugar, salt, and baking powder in a medium bowl. Cut in the butter with a pastry blender or two knives until you have pea-sized crumbles. Gently mix in beaten egg. Spray a 9×13 baking dish with non-stick cooking spray. Gently pat about 2/3 of the crumb mixture onto the bottom of the dish. Preheat oven to 350 and set aside.

To prepare the apple filling, combine the flour, sugar, and cinnamon and toss with apples. Spread the apples out on prepared crust. Sprinkle reserved crust mixture over apples evenly and bake in preheated oven for 40 minutes. When finished, allow to cool completely.

To prepare the glaze, whisk together the powdered sugar, almond extract, and enough milk to achieve desired consistency. Drizzle glaze over cooled pastry and allow to harden. Cut into bars and serve.