Step 1

Preheat oven to 350°F. Grease one 9" cake pan and line the bottom with parchment paper.

Step 2

Toss chopped peanut butter cups with 1 Tbsp of flour, set aside.

Step 3

In a mixing bowl cream butter, peanut butter and sugar until light and fluffy. Beat in eggs, 1 at a time.

Step 4

In a separate bowl sift together the flour, baking soda and salt. At low-speed, add the flour mixture alternately with the buttermilk.

Step 5

Add the chopped peanut butter cups to the batter. With a spatula mix until combined.

Step 6

Spoon batter in the prepared pan and spread evenly. Bake cake 33-35 minutes or until a toothpick inserted in the middle comes out clean. Cool cake 5 minutes. Turn out onto rack, peel off parchment. Cool cake completely before frosting.

Step 7

To make the frosting, in a mixing bowl add the butter, peanut butter and 1/3 cup heavy cream. Stir at low-speed until combined. Slowly add the powdered sugar, 1/2 cup at a time, mixing well after each addition. When all the sugar is added increase the speed and mix for 2 more minutes. If needed, slowly add few more drops of heavy cream.

Step 8

Frost the cake completely. Decorate with peanut butter cups.

Step 9

Keep cake covered. Serve at room temperature.