Vegetable shortening, for greasing bowls
16 oz. bag plain marshmallows, regular sized (I used jumbo and they worked fine as well)
2 tbsp. water
1-2 tsp. clear flavoring (I used vanilla extract)
2 lbs. confectioners' sugar, divided
Pinch of salt
Using the shortening, grease a large microwave-safe bowl, the bowl of the stand mixer, a spoon/spatula (or two), and the dough hook.
Add the marshmallows and water to the prepared microwave-safe bowl and microwave for 60 seconds. Stir with the greased spatula/spoon. If not all the marshmallows have melted, microwave for 30 more seconds. Stir in the flavoring.
Reserve 1 cup of the confectioners' sugar and add the rest to the bowl of the stand mixer, along with the salt. Create a well in the center. Pour the marshmallow mixture into the well and turn the mixer on to the lowest setting. When the mixer sounds strained, turn the speed up one setting. Turn off the mixer once all the sugar has been incorporated. If the fondant is sticky, add the reserved sugar 1/4 cup at a time until it is no longer sticky.
Turn the fondant out onto a piece of plastic wrap. Rub a bit of shortening on the outside of the ball. Wrap tightly with the plastic wrap, place it in a Ziploc bag and let rest for at least 2-3 hours. Keep the unused portions covered when not in use. If the fondant becomes stiff, microwave for 20 seconds at a time until it becomes pliable.
From: Annie's Eats