Apple Cinnamon Roll Cake

Preheat oven to 350F. Prepare an 8x8 baking pan by greasing it or lining it with parchment paper. Set aside. In a small bowl, combine the ingredients for the cinnamon-sugar topping then place in the fridge while you prepare the batter. In a medium bowl, combine the flour, baking powder, salt and cinnamon. Set aside. In another bowl, whisk together the egg, milk, sugar and vanilla. Fold in the flour mixture until almost combined. Stir in the melted butter. Fold in the apples, and pour the batter into the prepared pan. Grab the cinnamon-sugar topping out of the fridge and drop spoonfuls over the top. Take a butter knife and swirl the topping into the base. Bake for 28-30 minutes. While the cake is baking, prepare the glaze and set aside. Remove from oven and glaze the cake while still warm.