Fellow EtsyBlogger TwoZanyZebras shares the yummiest recipe on her blog. It's on my cooking list now.
BIG LEAGUE BROWNIES
Brownie mix with all ingredients needed
3/4 cup peanut butter
1/3 cup softened butter
1/3 cup sugar
2 T flour
Directions: Preheat oven to 350 degrees. Prepare brownie mix as directed. Set aside. Combine 3/4 cups peanut butter and softened butter until smooth. Add sugar and flour and mix. Add 2 eggs and blend well. Spread 1/2 brownie mixture in pan. Spread filling evenly over brownie mix. Spread remaining brownie evenly. Bake 30-33 minutes.