Total Calories: 51
Line an 8 x 8 x 2-inch baking pan with waxed paper. In a 2-quart saucepan over low heat, melt butter and chocolate. Remove from heat.
Stir in corn syrup, half-and-half or milk, and vanilla until blended. Add powdered sugar. Stir until blended and smooth, adding marshmallows or nuts at the end. Spread in pan. Refrigerate for 30 minutes. Cut into squares. Cover and store in the refrigerator.