1 1/2 cups all-purpose flour
1/4 cup unsweetened baking cocoa
1 teaspoon baking soda
1/2 cup butter margarine, softened to room temperature
3/4 cup dark brown sugar
1/2 cup granulated sugar
1 large egg
1 teaspoon vanilla extract
1 cup semisweet chocolate chips
Mix flour, cocoa and baking soda; set aside.
Blend butter, sugars, egg and vanilla in large bowl with mixer at medium speed until smooth.
Stir in flour mixture until blended; stir in chips.
Press dough in greased 13 x 9 x 2-inch baking pan.
Bake at 375º F (175º C) for 18 minutes or until done.
Cool completely; cut into bars.
Makes 24 bars.