1. Heat oven to 350°F. Remove wrappers from chocolates. Cutting from corner to corner, cut each chocolate into four triangles; set aside.
2. Beat butter, sugar, water and vanilla in large bowl on medium speed of mixer until well blended. Add egg; beat well. Stir together flour, cocoa, salt and baking soda. Gradually add to sugar mixture, beating on low speed just until blended. (If necessary, refrigerate dough until firm enough to handle.)
3. Roll dough into 3/4-inch balls. Place on ungreased cookie sheet. Bake 6 to 8 minutes or until cookie is set; remove from oven. Immediately place 2 triangle pieces on each cookie; allow candy pieces to soften. Using wooden pick spread only chocolate portion along outer edges of cookie to fill in surface edge. Swirl remaining creme de menthe center through chocolate to give swirled effect. Remove cookies to cooling rack; cool completely. Makes about 7 dozen cookies.