16 ounces semisweet chocolate, melted
1 (14 ounce) can sweetened condensed milk
2 teaspoons vanilla extract
1 1/2 cups chopped walnuts

Once chocolate is melted, stir in sweetened condensed milk. Stir in vanilla and walnuts. Spread into a greased 8-inch square pan. Refrigerate until firm. Cut into squares.