Mix brownies accornding to package (do not use cake like directions). Pour into 9X13 glass pan and bake 20-30 min at 375, checking for doneness at 20 minutes and every 5 after. Remove from oven and let cool.
While cooling, mix Peanut butter & oil together. In a separate dish put the frostings and set aside.
When brownies are cool spread peanut butter mixture over the top.
Refrigerate for 20-30 minutes.
Microwave frostings and mix together until pour-able and smooth. Pour frosting over brownies/peanut butter and spread around.