1 (16 oz.) can lemon pie filling
1 (15 oz.) package yellow cake mix
4 oz. cream cheese, cubed
1/2 cup (1 stick) unsalted butter, thinly slice
Preheat oven to 350º F and lightly grease a square baking dish with butter or non-stick spray.
Pour lemon pie filling into the bottom of greased baking dish, making sure to spread it into the corners.
Top with 1/2 cake mix, place cubed cream cheese evenly on top, then sprinkle remaining cake mix.
Take butter pats (as thinly sliced as possible) and place them in a single layer on top of the cake mix, trying to cover as much of the surface of the cake as possible.
Place baking dish in oven and bake for 35-40 minutes, or until toothpick inserted in center comes out clean.
Remove from oven and let cool 15-20 minutes before serving.