First set of ingredients:
1 pkg. plain yellow cake mix
1 stick melted butter
1 c. creamy peanut butter
Second set of ingredients:
1. Combine first set of ingredients and press into a 9X13 pan reserving 1 1/2 c. of the mixture to crumble on top.
2. Melt the second set on low heat in a small pot. Remove from heat and add 2 tsp. vanilla.
3. Spread chocolate mixture over the mixture pressed in the pan and then crumble the 1 1/2 of reserved cake mixture on top. Bake for 20-25 minutes at 325 degrees.
4. Cool completely before cutting into bars.