PB Cake Bars

a different twist on cake mix bars.  Mrblocko who claims he doesn't care for pb desserts loved this one.  Was a good summer dessert as it only required 12 min in oven.

Peanut Butter Cake Bars via Something Swanky
1 Devil's Food Cake mix
1/3 c butter, melted
1 egg
3/4 c peanut butter (I used smooth)
2 t vanilla
3 c powdered sugar
1/2 c whipping cream
optional: 2 tablespoons of milk for thinning if necessary
1 can of store-bought chocolate frosting

Preheat oven to 350ºF. Line a 9x13 baking dish with parchment and spray with PAM.In lg bowl mix cake mix, butter and egg. Press evenly into prepared dish. Bake 12 min. Cool completely in pan.
Meanwhile: In lg bowl combine pb and vanilla. Beat w electric mixer on med 30 sec. Add powdered sugar and whipping cream and beat until smooth, scraping bowl occasionally. If mix too thick, add 1-2 T milk to thin. Spread over cooled crust. Chill bars 30 min. Nuke frosting for 30 sec.  Make sure you've got all the foil off the top of the container. Spread  over peanut butter layer. Refrigerate for 2-3 hrs before serving.