Line 8-or 9-inch square pan with foil. In microwave, melt chocolate chips with sweetened condensed milk and salt on high for 2-3 minutes or until chocolate is almost melted, stirring halfway through heating time. Stir in walnuts and vanilla. Spread evenly into prepared pan. Refrigerate 2 hours or until firm. Remove from pan; place on cutting board. Peel off foil; cut into squares. Store loosely covered at room temperature.
About 5 dozen pieces or 2 pounds.
Optional:
Rocky Road Fudge: Add 1 cup miniature marshmallows with vanilla and walnuts.
Peanut Butter Fudge: Omit walnuts. Drop 1/2 cup peanut butter by teaspoonfuls on top of fugde. Swirl with knife to mable-ize.
Peppermint Fudge: Omit vanilla and walnuts. Stir in 1/2 cup crushed peppermint candies.
Coconut Walnut Fudge: Add 1 cup flaked coconut, toasted with vanilla and walnuts. Garnish with additional coconut.