1 1/4 cups butter, softened, 1 cup packed brown sugar, 1/2 cup sugar, 2 eggs, 3/4 t. vanilla extract, 4 cups flour, 1 t. baking powder, 1 t. salt, 1/3 t. baking soda, Red and Green food coloring, 1 square (1 oz) unsweetened chocolate melted and cooled.
In a large mixing bowl cream butter and sugars. Beat in eggs and vanilla. Combine flour, baking powder, salt, and baking soda; gradually add to creamed mixture. Divide dough into fourths. Tint one portion red and one portion green. Stir chocolate into another portion. Wrap chocolate and plain portions in plastic wrap; chill for 1 hour or until easy to handle.
For pinwheel cookies, divide red and green portions in half. Roll out each portion between waxed paper into a 9" x 6" rectangle. Refrigerate for 30 minutes. Remove waxed paper. Place one green rectangle over a red rectangle. Roll up tightly jelly-roll style, starting with a long side; wrap in plastic wrap. Repeat. Chill for 2 hours or until firm.
For Checkerboard cookies, divide plain and chocolate portions in half. Roll out each portion between waxed paper into 6" x 4" rectangle. Cut each rectangle lengthwise into eight 1/2" strips. Stack the strips in groups of four, alternating plain and chocolate strips and forming eight separate stacks. Form a four-stack block by alternating chocolate-topped and plain-topped stacks. Repeat. Press together gently. Wrap in plastic. Chill for at least 2 hours.
Unwrap and cut pinwheel and checkerboard doughs into 1/4" slices. Place 1" apart on ungreased baking sheets. Bake at 375 degrees for 9 - 11 minutes or until set. Remove to wire racks to cool. Yield: 6 dozen pinwheel and 4 dozen checkerboard cookies.