I make my own marshmallow fondant. I've noticed when roll it out, it's not quite as smooth as ready made fondant. I tend to get tiny lumps if icing sugar and a lot of air bubbles (which I think is from the marshmallow).

Does anyone else have this problem any any tips on how to make the marshmallow fondant better?

Do you sift your powdered sugar to get rid of the lumps?

Yes I do and I use a fine sieve.