In a medium saucepan, combine apples, granulated sugar, 1/2 tsp cinnamon, cornstarch and water. Heat on medium heat for 5-6 minutes until apples soften and the liquid thickens. Set aside to cool.
Cake
3 4 Preheat oven to 350°F. Coat a 9×13 pan with nonstick spray. Set aside.
5 In large bowl, mix the butter and sugar together for 3 minutes until fluffy.
6 Add the applesauce, vanilla, and eggs and mix on medium until combined, scraping the sides of the bowl as necessary.
7 In a separate bowl whisk together flour, baking powder, baking soda, salt, and cinnamon.
8 Add the dry mixture and the Greek yogurt in alternating parts, starting and ending with the dry. Mix until just combined.
9 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.
10 Cover with the remaining batter and sprinkle the remaining 1/3 of the brown sugar all over the top.
11 Bake 35 minutes and then start checking temperature of cake. Cake is done when the center reaches 205 degrees.