Melt 5 oz of the Mint Wafers (Ghiradelli brand is good) in a double boiler, stirring constantly or microwave on medium for about 3 minutes. Set aside. Cream butter with sugar, egg and salt. Mix in melted chocolate. Gradually add flour. Chill dough at least 1 hour. Shape dough into balls, using 1 level Tablespoon for each cookie. Roll balls into nuts. Place on greased baking sheets. Flatten slightly with the palm of hand. Bake at 350-F for only 8 minutes. Remove from oven and place Mint Wafer on top of each cookie, pressing slightly. Continue baking 3-5 minutes longer or until cookie is firm.