Line 9x9 or 13x9 pan with foil so that foil extends over sides of pan; butter foil. In a large saucepan, combine sugar, margarine, and eggnog. Bring to a boil over medium heat, stirring constantly. Boil 5 minutes, stirring constantly. Remove from heat. Add marshmallow cream and vanilla coating; blend until smooth. Stir in walnuts and extract. Pour into pan. Cool to room temperature. Score the fudge into 36 or 48 squares. Refrigerate until firm. Remove fudge from pan by lifting foil; remove foil from sides of fudge. Using large knife, cut through scored lines. Store in refrigerator.
