1-1/2 cups semi-sweet chocolate chips, divided
3-1/2 cups sugar
1-1/2 cups (12 oz. can) evaporated milk
1/2 cup (1 stick) butter
2 tablespoons light corn syrup
1 tablespoon white vinegar
2-1/2 cups Reese?s creamy or crunchy peanut butter
1 jar (7 oz.) marshmallow creme

Line 13 x 9 x 2-inch pan with foil. Place 1 cup chocolate chips in large heatproof bowl. In 4-quart saucepan, combine sugar, evaporated milk, butter, corn syrup and vinegar. Cook over medium heat, stirring constantly, until mixture comes to full rolling boil; boil and stir 5 minutes. Remove from heat. Add peanut butter and marshmallow creme; stir until smooth. Pour one half of peanut butter mixture over chocolate chips, stir until smooth. Pour chocolate mixture into prepared pan; top wit remaining peanut butter mixture. Immediately sprinkle remaining 1/2 cup chips over surface. With knife or metal spatula, gently swirl chips for marbled effect. Cool. Cut into squares. If firmer fudge is desired, store covered in refrigerator. Makes about 8 dozen pieces or 4 pounds candy.