Peppermint Whoopie Pies

Preheat oven to 350°F. In medium bowl, combine flour, cocoa powder, baking powder, baking soda and salt; set aside.

In large bowl, cream butter and brown sugar with electric mixer until light and fluffy. Add egg and extracts; mix well. Slowly add flour mixture and buttermilk, alternating, beginning and ending with flour mixture. Cover dough and chill at least 30 minutes.

Drop dough by rounded tablespoons onto parchment-lined baking sheet, placing cookies 2 inches apart. Bake cookies 9 to 12 minutes, or until firm. Cool cookies on pan 3 to 5 minutes or until set, then transfer to wire rack to cool completely.

For filling, in large bowl, cream together butter, fluff, and vanilla extract until light and fluffy. Add powdered sugar slowly; mix well. Spread flat side of half the cookies with heaping tablespoon of filling; top with second cookie to create sandwich. Roll edges in crushed peppermint candies; chill cookies to set filling.

Store unfilled cookies and filling in airtight containers in refrigerator for up to 1 week, and filled cookies for up to 3 days. Bring cookies to room temperature before serving.