• Cream butter or margarine, and sugar in a mixing bowl until fluffy (3-5 minutes)
• Add in eggs and vanilla and beat well.
• In a separate bowl, sift together flour, cocoa powder, baking powder, baking soda, and salt.
• Add the flour mixture to the creamed butter mixture, and add in the milk, mixing well.
• Press into slabs, and refrigerate for 1-2 hours or overnight.
• Shape dough into two 10 x 1 1/2 inch rolls and wrap each roll into wax paper; chill for several hours or overnight. Alternativly, refrisgerate the dough to be rolled out flat and cut out with cookie-cutters
• When you take the dough out of the refrigerator, let it sit on the counter for about 10 minutes that way it is easier to work with.
• Roll the dough to 1/8 inch thick and use biscuit cutters to cut circles
• Bake slices on un-greased cooking sheet at 325 degrees for 9 min.
• Let the cookies sit on the cookie sheet for 5 minutes, then remove and place them on a wire rack so they can cool
• .Once the cookies are fully cooled, assemble the cookies sandwich-style with the mint filling

Filling

• Whip together room-temperature butter, powdered sugar, and milk in a bowl until smooth and creamy. Add the peppermint extract or essential oil. Mix well!