Ingredients:

3/4 cup all purpose flour
1/4 cup unsweetened cocoa
1/4 tsp baking soda
1/8 tsp salt
1/4 stick margarine, softened
2/3 cup granulated sugar
1 tsp vanilla extract
1 large egg white
2 Tblsp turbinado sugar
Vegetable cooking spray

Combine the first four ingredients in a bowl and set aside. Beat the margarine at medium speed with an electric mixer until light and fluffy. Gradually add granulated sugar, beating until well blended. Add vanilla and egg white; beat well. Add flour mixture, and stir until well blended. Turn dough out onto wax paper; shape into a 6 inch log. Wrap log in wax paper and freeze for 3 hours, or until very firm.

Preheat oven to 350F. Roll the frozen log in turbinado sugar. Cut the log into 24 (1/4-inch) slices; place 1 inch apart on a baking sheet coated with cooking spray. Bake at 350F for 8 to 10 minutes. Remove from sheet, and cool on wire racks.

As a variation, 1 tsp peppermint extract can be substituted for the vanilla extract.