I use a simple marshmallow fondant recipe i found online; water, sugar and marshmallows. When ever I put it on my cake, a few minutes it comes out all lumpy. Any comments, advice, suggestions? do I try a new fondant or recipe, anything? thanks for the help, I appreciate everything and anything!

Your frosting underneath has to be smooth. Whatever is going on under the fondant is reflected in the surface of the fondant. Is that what you mean?

It may very well be that the frosting that you put under the fondant is slightly soft. I have had it happen where I had my cake chilled and the frosting was firm, but a few minutes after the fondant went on it, it sortof drooped, as the frosting underneath came back up to room temp. So you could try thicker frosting. HTH!

thank you everyone for all your advice

You may be rolling your fondant too thin as well or it could not have enough powdered sugar too it and be too sticky as well. If you are sure you have your consistancy of the MMF correct (like soft pizza dough) then make sure not to roll it too thin. Also, make sure to put it on a thin smooth crumbcoat on and let the cake get to room temp and settled for about 2 hours. This means your crumbcoat has had time to crust and your cake has had time to settle and any filling can be smoothed out as well as any gas that needed to escape has escaped. Then you can cover with the fondant and have it go on smoothly and, hopefully, not get any gas bubbles. Too thick of buttercream, too soft of buttercream, not smooth enough buttercream as a base as well as too cold of a cake that has not settled will all give you bumps and bubbles in your fondant. Too thin of a fondant will show every single imperfection in your undercoat so roll it about the thickness of a nickle or so. HTH. Cat