Preheat oven to 350°.
Grease 2, 9 inch cake pans or line with parchment paper.
Prepare the brownie mix as per instructions on box.
Pour ½ of batter into each cake pan.
Bake for 8-10 minutes until partially baked.
While brownie mix is baking, prepare cake mix according to instructions on box.
When the brownies come out of the oven, pour ½ of the cake mix into each cake pan.
Bake an additional 20-25 minutes or until toothpick inserted comes out with crumbs.
Frost after cooling.
Chef's notes: Don't let brownie layer overcook or it will be dry and tough. Use any frosting you like. If making in a 9X13 inch baking dish, use brownie mix for 9X13 inch baking dish. Cut the baking time on the brownie mix to 5-8 minutes and the final bake time start checking for doneness at 15 minutes, then 5 minute increments until done.