1. Heat oven to 350°F.
2. Beat butter, granulated sugar, brown sugar and vanilla in large bowl on medium speed of mixer until creamy. Add eggs; beat well. Stir together flour, cocoa, baking soda and salt; gradually add to butter mixture, beating until well blended.
3. Drop dough by slightly heaping 1/4 cupfuls onto ungreased cookie sheet, about 3 inches apart (put only 4 on a cookie sheet). Shape into balls. With palm of hand, flatten to 3-1/2-inch rounds.
4. Bake 8 to 10 minutes or until set. (Cookies will spread during baking; baked cookies will be about 5 inches in diameter.) Cool 3 minutes; using a wide spatula, carefully remove from cookie sheet to wire rack. Cool completely.
5. Make a pattern of child's hand on paper, with fingers spread. Cut out the pattern; place pattern on cookie. Using pattern as a guide, outline hand with icing; repeat with remaining cookies. Garnish if desired. Makes 12 to 14 cookies.