- 1 ¼ cups all-purpose flour
- ½ cup unsweetened cocoa powder
- ¼ teaspoon salt
- ½ cup butter, softened
- 1 cup white sugar
- 1 egg
- ½ teaspoon mint extract
- 3 (1 ounce) squares semisweet chocolate, chopped
- ¼ cup butter
Beat 1/2 cup butter in a large bowl until creamy. Add sugar and beat until mixed well. Beat in egg and mint extract.
Sift flour, cocoa, and salt together into a small bowl. Add flour mixture, in two portions, into creamed mixture, beating well after each addition.
Divide dough in half. Roll dough on a lightly floured surface into two 1 1/2-inch diameter cylinders. Wrap each cylinder in waxed paper; refrigerate 5 hours.
Preheat the oven to 350 degrees F (175 degrees C). Place both cylinders in the freezer 30 minutes before baking.
Working with one cylinder at a time, slice 1/4-inch-thick pieces with a very sharp knife. Place on cookie sheets about 1 1/2 inches apart.
Bake in the preheated oven, 10 to 12 minutes.
Melt chocolate and 1/4 cup butter in a double boiler or the microwave. Drizzle over warm cookies. Place cookies on a wire rack to cool and harden completely.