In large glass bowl, microwave the butter until it has melted. Add the sugar and milk; whisk together well.
Microwave on high for 3 minutes, then stir, then microwave on high 2 minutes more.
Mix well; scraping the sides of the bowl. Microwave on high for 3 more minutes, then stir and measure temp. You're looking for it to reach 234 degrees F. Microwave for 1 to 2 more minutes until 234 degrees is reached.
Remove from the microwave and add the chocolate chips. Stir vigorously until melted and smooth. Add the marshmallow creme and the vanilla extract; mix well until you no longer see any white streaks. Pour into a greased 9-inch square pan, or 13x9-inch baking pan (depending on how thick you would like your fudge)- I used 9x9-inch for the photo.
Cool completely at room temperature. Cut into squares.
Notes
*If you are a nut-family, by all means add in 1 cup chopped walnuts!
*Keep fudge in a covered container. It should keep for a week or two when stored well.
*This recipe is gluten-free adaptable. Just be sure to use a brand of chocolate chips that is known to be GF.
*To make this fudge on the stove instead: Bring sugar, butter and evaporated milk to full rolling boil in 3-qt. saucepan on medium heat, stirring constantly. Cook until a candy thermometer reaches 234°F, stirring constantly. This should take around 4 minutes. Remove from heat. Whisk in the chocolate until melted. Then mix in the marshmallow creme and vanilla extract. Scrape into a pan and cut in the same manner as the microwave version.