Step 1

Preheat oven to 350 degrees. In a large bowl, combine the flour, the baking soda, the baking powder, and the salt. Set aside.

Step 2

In a large bowl, beat the butter and the peanut butter together until fluffy. Add the sugars and beat until smooth. Add the egg and mix well. Add the milk and the vanilla extract. Add the flour mixture and beat thoroughly. Scoop dough into greased muffin tin and fill half way.

Step 3

Bake for 12-14 minutes, or until lightly browned. Remove from the oven and press down the middle of the cookie with any round object in your kitchen, (I used the bottom of an ice cream scooper) or you can even use your thumb. Let cookies cool, then fill with chocolate buttercream.

Step 4

Chocolate Buttercream:

Step 5

Beat butter and vanilla at medium high speed for 30 seconds. Add powdered sugar and cocoa until combined, and slowly add in milk and corn syrup. Beat on high until you reach desired consistency. You may need to add more milk, or more powdered sugar depending on how thick you like your buttercream. Place in piping bag and fill cookies. Enjoy!

Step 6

(Makes roughly 24 cookies)