Here are the results from my recent Gooey Butter Cake experiments:
Chocolate Malt Gooey Butter Cake (My New Favorite)
For Crust:
1 box cake mix, yellow or chocolate
4 oz Melted Butter
1 Egg
Combine above and press in to the bottom of a 9 x 13 Cake Pan
For Filling:
8 oz Cream Cheese
4 oz melted butter
2 Eggs
1 lb Powdered Sugar
4 Tbs Cocoa Powder, Hershey's Special Dark worked best of the ones I've tried
4 Tbs Malted Milk Powder
Cream together cream chesse, butter & eggs until smooth. sift together remaining ingredients and slowly add to the cream cheese mixture. Pour over crust and bake for 30-40 Minutes at 350. The filling shouldn't be firmly set, but should still show motion when shaken.