Peanut Butter Truffle Brownies

This recipe came from Betty Crocker's website.  These are so easy and so good.  My husband has forbid me to make these cause he always wants to eat the whole pan.

Brownie Box

1 box (1lb 6.5 oz) Betty Crocker Original Supreme Brownie Mix
Water, vegetable oil and eggs called for on brownie mix box

Filling

1/2 cup butter, softened
1/2 cup creamy peanut butter
2 cups powdered sugar
2 teaspoons milk

Topping

1 cup semisweet chocolate chips
1/4 cup butter

Heat oven to 350.  Grease bottom of 13 x 9 pan with cooking spray. 
In medium bowl, stir brownie mix according to box directions.  Spread in pan.  Bake 28 - 30 minutes or until toothpick  inserted comes out clean.  Cool completely, about an hour.
In medium bowl, beat filling ingredients with electric mixer on medium speed until smooth.  Spread mixture evenly over brownie base.
In small microwavable bowl, microwave topping ingredients uncovered on high 30-60 seconds; stir until smooth.  Cool 10 minutes; spread over filling.  Refrigerate about 30 minutes or until set.  For brownies, cut into 9 rows by 4 rows.