Filling

1. In a medium saucepan combine apples, granulated sugar, cinnamon, cornstarch and water.
2. Heat on medium heat for 5-6 minutes until apples soften and the liquid thickens. Set aside to cool.
3. Mix the dark brown sugar and remaining 1/2 teaspoon cinnamon in a small bowl and set aside.

Cake

1. Preheat oven to 350°F. Coat a 9×13 pan with nonstick spray. Set aside.
2. In the bowl of your stand mixer, fitted with the paddle attachment mix the butter and sugar together for 3 minutes until fluffy.
3. Add the applesauce, vanilla, and eggs and mix on medium until combined, scraping the sides of the bowl as necessary.
4. In a separate bowl whisk together flour, baking powder, baking soda, salt, and cinnamon.
5. Add the dry mixture and the Greek yogurt in alternating parts, starting and ending with the dry. Mix until just combined.
6. Spread 1/2 of the cake batter in the bottom of the prepared pan. Top with the apple mixture, spreading carefully to cover the batter. Then top with 2/3 of the brown sugar, sprinkling all over the apple mixture.
7. Cover with the remaining batter and sprinkle the remaining 1/3 of the brown sugar all over the top.
8. Bake 35-40 minutes, or until the center of the cake is set.

Glaze

1. When the cake has only a few minutes left baking, prepare the glaze by mixing the powdered sugar, milk and vanilla in a medium bowl until smooth.
2. When cake is done, immediately poke holes in the cake using a butter knife, about 30 pokes.
3. Pour the glaze over the top of the cake spreading to cover it completely. Let the glaze set up for about 20 minutes before serving.