Move rack to the middle of the oven. Preheat oven to 350F. Spray 9x13 inch pan liberally with non stick spray, set aside.
In a bowl gently combine dry angel food cake mix with lemon pie filling just long enough for the dry mix to be integrated, no longer. Best to use a rubber spatula slowly to combine.
When oven is preheated add batter to pan and smooth out so it is the same thickness all the way across the pan.
Bake for 30 minutes. Remove from oven and set on cooling rack until it is completely cooled before slicing and serving with a bit of powdered sugar sprinkled on the top.