In small saucepan, melt butterscotch chips over low heat, stirring constantly until smooth.
In large bowl, combine sugar, brown sugar, margarine and melted chips; beat until smooth. Add milk, vanilla and egg; blend well. Lightly spoon flour into measuring cup; level off. Add flour; mix well.
Divide dough in half. To half of dough, stir in cocoa until well blended. Wrap each half of dough in plastic wrap; refrigerate 1 hour for easier handling.
Heat oven to 375°F. On well-floured surface, roll out each half of dough to 1/8-inch thickness. Cut with 2 1/2-inch round cookie cutter. Place 1 inch apart on ungreased cookie sheets. Refrigerate cutouts 15 minutes. Using small leaf-shaped cookie cutter, cut out center of each round cutout; replace with center of opposite color.
Bake at 375°F. for 5 to 8 minutes or until set. Cool 1 minute; remove from cookie sheets.