18.3oz(520g)box family size brownie mix, (for a 13×9" pan)
Ingredients for brownie mix. Mine called for:
½cup(118ml)vegetable oil, *use amount listed on box
¼cup(59ml)water, *use amount listed on box
2large eggs, *use amount listed on box
Peanut Butter Buttercream:
½cup(113g)unsalted butter, (1 stick) softened
1cup(264g)creamy peanut butter
pinchsalt
2 ½cups(300g)powdered sugar
1tspvanilla extract
1-2Tbspmilk
Chocolate Glaze:
1cup(170g)semi-sweet chocolate chips
¼cup(66g)creamy peanut butter
Instructions
Make brownies according to directions on the box for a 13x9" pan. Grease the pan well before adding batter & baking. Allow brownies to cool completely.
Make the peanut butter buttercream by creaming the butter, peanut butter, & pinch of salt in a stand mixer until all lumps of butter are smooth. Add powdered sugar & vanilla. Mix. Add milk gradually until spreading consistency. Spread PB buttercream over the top of the cooled brownies.
Melt the semi-sweet chocolate chips & peanut butter in the microwave in short bursts, stirring frequently. (I do 30 seconds, stir, 15 seconds, stir 15 seconds stir...until it's melted.) Pour chocolate mixture over the PB buttercream. Smooth with a spatula. You can create a pretty design by zig-zagging the chocolate layer from one corner of the pan to the opposing corner. Then dragging the tip of your spatula (or use the tip of a knife) to draw lines back & forth across the zig-zag pattern.