Preheat oven to 350* F.

In top of double broiler over low heat, melt semisweet chips and butter, stirring constantly until smooth. Set aside to cool. In small bowl combine flour, baking soda and salt; set aside.

In large bowl beat eggs, sugar and vanilla until light. Blend in melted chocolate then dry ingredients. Stir in green mint chips and chill for 10-15 minutes. Drop by well rounded teaspoonfuls onto ungreased cookie sheets. Bake 8-10 minutes; cookies will be soft in the centers and harden as they cool.