Swirled Mint Cookies

In a large mixing bowl, beat butter with an electric mixer on medium to high speed for 30 seconds. Add 1 cup sugar, and baking powder. Beat until fluffy. Beat in egg, vanilla and peppermint extracts. Stir in flour until just mixed Divide dough into 3 equal portions. Stir red food coloring into one portion; stir green food coloring into a second portion; and leave third portion plain. Cover each portion with foil or plastic wrap and chill about 1 hour or until easy to handle. Divide each color of dough into 4 equal portions. On a lightly floured surface, roll each portion into a 1/2-inch diameter rope. Place a red, green and plain rope side by side. Twist together. Repeat with the remaining ropes. Chill twisted ropes for 30 minutes. Cut the ropes into 1/2-inch slices for larger cookies and 1/4-inch slices for smaller ones. Carefully roll into balls, blending colors as little as possible. Place balls about 2-inches apart on an ungreased cookie sheet. Using a glass dipped in additional sugar, flatten each ball of dough to 1/4-inch thickness. Bake in a 375 °F (190 °C) oven for 8 to 10 minutes for larger cookies (6 to 8 minutes for smaller ones) or until edges are set. Transfer cookies to a wire rack to cool completely.