Prepare the cake mix in a large mixing bowl as directed on the box. Mix in two tablespoons of cinnamon. Evenly pour the cake batter into a greased 9 x 13 pan.
Top the cake batter with spoonfuls of apple pie filling. you can add extra cinnamon to the apple pie mix
Streusel
Mix the brown sugar and melted butter until smooth. Mix in the sea salt, flour, and ground cinnamon. The streusel should be crumbly. To thicken up the streusel, add more flour. If it's too dry, add in more butter.
Evenly distribute the streusel over the apple pie filling.
Bake for 28-32 minutes. Let the cake cool for about twenty minutes before adding the glaze. You want the cake to be slightly warm.
Glaze
Mix the melted butter, maple syrup, milk, and powdered sugar in a small mixing bowl.
Evenly distribute the glaze over the slightly warm cake.
Slice into 20 squares. This cake (and most cakes) is best when stored in the refrigerator.