1. Beat butter, sugar, egg and vanilla in large bowl until fluffy. Stir together flour, cocoa, baking powder, baking soda and salt; add to butter mixture, blending well. Refrigerate about 1 hour or until firm enough to roll. Cut cardboard rectangle for pattern, 2-1/2 x 4 inches; wrap in plastic wrap.
2. Heat oven to 350°F. Lightly grease cookie sheet or line with parchment paper. On lightly floured board or between two pieces of wax paper, roll out half of dough to 1/4-inch thickness. For each cookie, place pattern on dough; cut through dough around pattern with sharp paring knife. (Save dough trimmings and reroll for remaining cookies.) Carefully place cutouts on prepared cookie sheet.
3. Bake 8 to 10 minutes or until set. Cool 1 minute on cookie sheet. (If cookies have lost their shape, trim irregular edges while cookies are still hot.) Carefully transfer to wire rack. Repeat procedure with remaining dough.
4. Prepare DECORATIVE FROSTING; spoon into pastry bag fitted with decorating tip. Pipe names or greetings onto cookies; decorate as desired. Makes about 12 cookies.
DECORATIVE FROSTING: Beat 3 cups powdered sugar and 1/3 cup shortening in small bowl; gradually add 2 to 3 tablespoons milk, beating until smooth and slightly thickened. Cover until ready to use. If desired, divide frosting into two bowls; tint each a different color with food color.