Hershey's Double Chocolate Mint Cookies

2/3 cup butter, softened

1 cup sugar

1 egg

1 teaspoon vanilla

1 cup flour

1/2 cup cocoa

1/2 teaspoon baking soda

1/4 teaspoon salt

1 2/3 cups (1, 10 oz. bag) Hershey's mint chocolate chips

Preheat oven to 350. Beat butter and sugar until creamy. Add egg and vanilla. Mix well. In a separate bowl combine flour, cocoa, baking soda, and salt. Gradually add to the butter mixture, beating well. Stir in the chocolate chip by hand. Drop by rounded teaspoonfuls onto ungreased cookie sheets. Bake for 8-9 minutes or until just set; do not overbake. Cool slightly; remove from cookie sheets to wire racks. Cool completely. Makes about 2 dozen.