1 can (12 ounces) evaporated milk
1 cup butter or margarine
1 package (8 ounces) cream cheese, softened
2 jars (7 ounces each) marshmallow creme or 1 package (10 1/2 ounces) miniature marshmallows
1 tablespoon vanilla
1 package (12 ounces) white baking chips (2 cups)
1 cup milk chocolate chips
1 package (6 ounces) semisweet chocolate chips (1 cup)
2 tablespoons baking cocoa
1/2 cup chopped nuts, if desired
Butter rectangular pan, 13x9x2 inches, or line with aluminum foil, leaving 1 inch of foil overhanging at 2 opposite sides of pan. Heat sugar, milk, butter and cream cheese to boiling in 6-quart Dutch oven over medium-high heat and cook 6 to 8 minutes, stirring constantly. Reduce heat to medium. Cook about 10 minutes, stirring occasionally, to 225º on candy thermometer; remove from heat. Quickly stir in marshmallow creme and vanilla. Pour 4 cups hot marshmallow mixture over white baking chips in large bowl; stir to mix. Stir milk chocolate chips, semisweet chocolate chips, cocoa and nuts into remaining marshmallow mixture. Pour one-third of the white mixture into pan, spreading evenly. Quickly pour one-third of the chocolate mixture over top, spreading evenly. Repeat twice. Swirl knife greased with butter through mixtures for marbled design. Cool until set. Refrigerate uncovered about 3 hours or until set. Cut into 12 rows by 8 rows with knife greased with butter. Store covered in refrigerator.