I am decorating cakes tonight for my kids birthday party tomorrow, One of them is frosted in buttercream with a pudding filling so I know that one has to be refrigerated, but the other cake is my first attempt at MMF fondant and I am wondering if I should refrigerate that one? It has a buttercream undercoating & buttercream filling, I used water and 1/2 shortening 1/2 butter to make it. Another question is what is the best way to apply shimmer dust and should I put that on tonight or do I need to wait until right before its served to keep the shimmer, is the process different if I am using it on MMF vrs. buttercream? Ok so I made a yellow Pillsbury cake mix for the MMF cake, I baked it at 1:00AM and it had a bit of a bump to it so I did the heavy plate thing I have read about on here, plus I had greased and floured the whole pan, and when I tried to turn it out of the pan it just crumbled. So off to the store I went this morning, got another yellow Pillsbury cake mix this time I made sure only to grease/flour the bottom, did not try the plate thing and my cake still crumbled. I am using ener-g egg replacement in both my cakes since I have a child allergic to egg, but the Pillsbury chocolate cake I made for the other cake turned out fine. (Btw I used Pillsbury because it is what Albertsons had on sale) What did I do wrong with my yellow cake? Thanks for any help, I have learned so much from this sight and with my kids food allergies I plan to get good at making cakes.

I dont know the answers to all of your questions, but I do know that you dont have to refrigerate MMF cakes...the shimmer dust doesn't lose its shimmer so put it on whenever ya want. Some people put lemon juice in theirs to paint it on but I never have. I just use a paint brush and dry brush it on. Works great for me!
Good luck!