All you need is: an angel food cake mix | lemon pie filling | confectioners sugar.
Mix the lemon pie filling with the cake mix. Be careful, though, because the cake mix is very light and it will seem like the two won't mix well. Then pour it into a 9x13 pan. I sprayed mine with a flour/cooking spray combo that you can get at the store. It helped keep the cake from sticking to the pan. Then bake in a preheated over at 350 degrees for about 20-25 minutes.
If you are so inclined, you can dust it with powdered sugar. To me this was less like a lemon bar and more like a light lemon cake. Try it out for yourself and tell me what you think!