Chocolate Mint Sandwich Cookies

Cookies:
3 cups all-purpose flour
3/4 cup unsweetened Dutch-processed cocoa
2 teaspoons baking powder
1/2 teaspoon salt
2 sticks (8 ounces) unsalted butter, room temperature
1 1/4 cups sugar
1 large egg, lightly beaten
1 egg yolk
1 1/2 teaspoons vanilla extract

Filling:
4 tablespoons cream cheese, room temperature and soft
4 tablespoons butter, softened
2 cups confectioners' sugar
1/2 teaspoon mint extract
Peppermint candies, for decorating

Heat oven to 350 degrees F. Line 2 baking sheets with parchment paper.

In a medium bowl, sift the flour with the cocoa, baking powder and salt.

In a large bowl, using a hand-held mixer, beat the 2 sticks of butter until creamy. Add the sugar and beat until light and fluffy, about 3 minutes. Add the egg, egg yolk and 1 teaspoon of the vanilla extract. Beat until well-blended.

Add the dry ingredients and beat at low speed until moistened and a stiff, crumbly dough forms. Scrape the dough onto a sheet of plastic wrap, pat into a disk, wrap and refrigerate until chilled.

Divide the dough into quarters. On a lightly floured work surface, working with one piece at a time and keeping the rest refrigerated, roll out the dough to 1/8-inch thickness. Using a 2-inch round cookie cutter, cut out as many cookies as possible and transfer to baking sheet. You will get more cookies than baking sheets. Put the cut cookies onto a sheet of parchment.

Bake 2 sheets of cookies in the oven for 10 minutes. Halfway through the baking, switch the shelves and rotate the pans from front to back to insure even cooking. When ready, remove the cookies from the oven. Sprinkle half of the cookies with crushed peppermint candies and return to the oven for a minute. Remove from oven and slide the parchment onto a cooling rack. Let cookies cool completely. Repeat with remaining cookies.

For the filling: In a medium bowl, beat the remaining 4 tablespoons of butter with the cream cheese until smooth. Beat in the confectioners' sugar, mint extract and remaining 1/2 teaspoon of vanilla extract. Spread 1 1/2 teaspoons of filling on the undecorated cookies and top with the decorated cookie.

Makes about 2 1/2 dozen sandwich cookies.