Preheat the oven to 350 degrees.
LIghtly grease the bottom and sides of a square baking dish.
Spread the lemon pie filling in the bottom of the dish, making sure to reach all sides.
Add 1/2 of the cake mix over the lemon pie filling.
Place cubed cream cheese evenly across the top. Then cover with the rest of the cake mix.
Top with the thin slices of butter, making sure to cover the top as much as possible.
Bake for 40 to 45 minutes or until toothpick inserted in the center comes out clean.
Allow the cake to cool for about 20 minutes before serving. Enjoy!