Heat 6 oz chocolate in heavy saucepan over low heat, stirring constantly until melted. Remove from heat. Stir in 2 tablespoons margarine, the half and half and 1/2 cup powdered sugar. Shape mixture into 1 inch balls and place on ungreased cookie sheet. Freeze uncovered about 30 minutes, until set.
Preheat oven to 350 degrees F (175 degrees C).
Mix 1/2 cup margarine, 3/4 cup powdered sugar, the vanilla and 1 oz chocolate. Work in flour and salt until dough holds together. (If dough is dry, mix in 1 or 2 tablespoons milk). Mold portions of dough around frozen chocolate balls to form 1 1/2 inch balls. Place about 1 inch apart on ungreased cookie sheet. Bake 12 to 15 minutes or until set but not browned. Remove from cookie sheet. Cool completely on wire rack.
