Line an 8" or 9" square pan with foil, butter the foil and set aside.
Combine, marshmallow creme, sugar, evaporated milk and butter in a heavy saucepan.
1 1/2 cups Granulated Sugar, 7 oz Marshmallow Creme, 5 oz Evaporated Milk, 4 Tablespoons Unsalted Butter
Cook over medium heat to a full boil, stirring constantly.
Once to a boil, cook for 5 minutes, stirring constantly. The fudge mixture will turn from a creamy white to a light caramel color.
Remove from the heat, stir in chocolate chips and vanilla.
12 ounces Extra Dark Chocolate Chips, 1/2 teaspoon Vanilla Extract
Stir until chips are melted thoroughly and pour into the prepared pan.
Let set until firm.