Preheat the oven to 350°. Prepare brownies according to package directions. Remove brownies from oven and press the peanut butter cups, bottoms down, into the warm brownies making rows that cover the entire top. Place brownies back into the oven for one to two minutes or until the peanut butter cups soften. Use a spatula or knife to spread softened peanut butter cups over brownies into a gooey frosting. Allow to cool (if you can). Enjoy!