If I am going to serve a cake on Friday at noon, do you think it's okay to make the buttercream on Wed. night, frost the cake, then leave in the fridge until Friday morning, then take the cake out to come to room temp during the morning? Is that enough time?
What about if I frost the cake and just leave the whole thing out for two days?
Is there a filling in the cake? If not then yes, frost it, refrigerate it & then let come to room temp.
Don't leave the cake out..especially if the temperature in the room is not always the same.
According to Rose Levy Beranbaum: A buttercream cake will keep for 1 day at cool room temperature.
A butter cake will keep refrigerated 3 days, a genoise 5 days. You must remove a butter cake 6 hours before serving for best texture, a genoise 2 hours to let the buttercream soften.