I am trying to make a guide to send with my customers on how to cut their cakes and store leftovers. Do you know how long a cake with buttercream icing and a cake with fondant will stay fresh at room temperature, refridegerated, and frozen? Any storing techniques for maximum freshness? Thanks a bunch!

freeze!! Once a cake is cut it can go south fairly quickly! I would tell them to wrap it up really well in plastic wrap then stick it in heavy duty foil and then into a bakery box (the cardboard will absorb odors from freezer) then wrap the box in plastic and foil. That's what I did with my anniversary tier on my wedding cake and it tasted awesome ONE YEAR later!

In case you have a client who wants to eat the leftovers right away, I had leftover cake from my daughter's baby shower a week later and it still tasted fresh as day one. I bake from a mix (baking from scratch might have a different result), and I just put loose saran over the plate of cake and shoved it in the bottom of my 'frig.