3/4 cup butter, softened
1 cup granulated sugar
1 teaspoon baking powder
1/4 teaspoon mint extract
green McCormick food coloring
2-1/4 cups all-purpose flour
6 Oreo cookies (regular flavor), finely crushed
1/2 cup semi-sweet chocolate chips
In a large mixing bowl, beat butter with an electric mixer for 30 seconds. Add sugar and baking powder and beat until combined. Beat in egg, mint extract, and a few drops of green food coloring until mixture reaches a mint green color. Stir in flour until well blended. Divide dough in half, wrap halves in plastic wrap and chill 1 hour or until somewhat firm.
Roll one half of dough between two sheets of waxed paper into an 8×7-inch rectangle. Peel off the top sheet of waxed paper and sprinkle half of the crushed Oreo cookies over the dough, to within 1/4 inch of sides. Starting from the short side, roll up dough and pinch to seal. Repeat with remaining dough and crushed Oreos. Wrap rolls in plastic wrap and stand upright in tall drinking glasses, then chill about 4 hours or until very firm.
Pre-heat oven to 375 F. Remove one roll of dough from refrigerator. Unwrap and slice into 1/4-inch slices. Place 2 inches apart on an ungreased baking sheet. Bake 8 to 9 minutes or until edges are firm but not brown.
Cool on baking sheet for 1 minute then remove to wire rack to cool completely. Repeat with other roll. When cooled, melt chocolate chips in the top of a double boiler over hot (not boiling) water. Transfer melted chocolate to a resealable plastic bag and with a scissors, snip off a tiny corner of the bag. Drizzle melted chocolate over cookies. Allow chocolate to set and harden, then store in an airtight container in layers separated by waxed paper for up to 3 weeks.