In a medium saucepan, combine the marshmallows and milk, stirring over low to medium heat until the marshmallows are completely melted.

Once melted, remove the saucepan from the heat and let the mixture cool slightly.

Gradually add the powdered sugar to the mixture while whisking vigorously to avoid lumps and ensure a smooth texture.

Mix in the vanilla extract or any flavoring of your choice and continue to whip until creamy and smooth.

Use the icing immediately to frost your cakes or cupcakes, as it works best fresh.

If desired, decorate with sprinkles, edible glitter, or fresh fruit.