In Russia, my grandmother used sour cream to make the frosting, because there was no such thing as heavy cream. My mom uses heavy cream now but part of me wonders what the flavor was like with sour cream.
The layers for the cake can be made up to a week in advance. Keep them covered with a plastic bag.
Assemble the cake at least a day in advance and keep it out of the fridge for at least a couple of hours right after assembling and before serving so that it has time to set and become moist with the frosting.