For anyone who has used the stackable cutter set and decorated with MMF....

what do you use to stick the cookie pieces to each other? I don't want the top layer cookie to pull off the MMF.

Any tips would be appreciated!
Thank you.

Can anyone help me? I'm assembling these today and don't want a disaster! lol

Do I have to cut out the fondant under the cookie layer that will sit on top? So that it's cookie to cookie?

I have used these cutters before and I use MMF all the time. Your MMF will tear once your remove the top cookie. I always use royal to stick them together or sometimes a little corn syrup. I really do not see an issue with them tearing because once they remove the top cookie it is because they are being eaten. The top cookie will not fall off once the royal icing dries. I not sure I am helping you but this is my experience. Good Luck.