Heat oven to 350'F. In large mixer bowl, beat butter and granulated sugar until light and fluffy. Add egg, corn syrup and peppermint extract; mix thoroughly. Dissolve 1 teaspoon instant coffee in water; stir into butter mixture. Stir together flour, cocoa, baking soda and salt; gradually add to butter mixture, blending thoroughly. Shape dough into 1" balls. (Dough may be refrigerated for a short time for easier handling.) Prepare Mocha Mint Sugar. Roll dough balls in sugar mixture. Place on ungreased cookie sheet, about 2" apart. Bake 8-10 minutes or until no imprint remains when toughed lightly. Cool slightly. Remove from cookie sheet to wire rack. Cool completely. Makes about 4 dozen cookies. MOCHA MINT SUGAR: In small bowl, stir together powdered sugar, peppermint candies and powdered instant coffee.