Step 1

Line a 8X8- or 9X9-inch pan with foil and lightly butter or grease with nonstick cooking spray. Set aside.

Step 2

In a large microwave-safe bowl, add the chocolate chips, marshmallows, sweetened condensed milk, butter and salt. Microwave for 45-second intervals, stirring in between, until the mixture is smooth and creamy; stir in the vanilla (or other flavored extract).

Step 3

Add any add-in ingredients, if desired (chopped nuts, M&M's, peanut butter chips, toffee bits, dried fruit, coconut, etc)

Step 4

Spread the fudge evenly in the prepared pan. Top with any additional garnishes, like chopped nuts or any of the suggestions listed above, pressing the ingredients lightly into the soft fudge. Cover the pan with plastic wrap and refrigerate for 1-2 hours until set (I mean, you CAN dig in right away, but it will be super soft and sticky...and super delicious! :). Cut into squares.

Step 5

The fudge will keep for several days, well-covered, in the refrigerator.