I am want to try making Meringue Buttercream but would like to know if you can use it with fondant and how long it can stay at room temperature. Thanks!

Swiss, Italian or French Meringue Buttercream ??

smbc can be used under fondant. its a debate on how long it can be left out. i do 3 days max, some say not at all. fondant cakes CAN be stored in the fridge.

The fondant provides a great seal to a cake. I use SBC/IMBC/ganache under fondant and it has been fine after 5 days.

I agree with CakeandDazzle. Frost, fondant, refrigerate.