Peanut Butter Truffle Brownies

These are sinfully delicious and you won't regret making them! Also, they're so stinkin' simple.

1 box brownie mix (9x13 pan size)-follow box directions

FILLING:
1/2 c. butter, softened
1/2 c. peanut butter (creamy or chunky both work fine)
2 -3 c. powdered sugar
2 t. milk
TOPPING:
1 c. chocolate chips
1/4 c. butter

Cook brownies per box directions; cool. Beat filling mixture and spread over brownies. Microwave topping; stir until smooth. Cool for about ten minutes and then spread over the top. Refrigerate before serving.