This recipe has two layers that are prepared before baking.
Bottom layer
  1/2 c. butter, melted
  1 beaten egg
  1 yellow cake mix
Combine and spread into a 9x13 buttered pan. 
?Topping
Combine: 1 c. brown sugar 
1 c. powdered sugar 
8 oz. cream cheese, room temperature 
1 tsp. vanilla 
1/8 tsp. salt
Beat until smooth and spread over cake mixture. 
Bake at 325 degrees for 40 to 45 minutes. Cut when cool and sprinkle with powdered sugar.