Since sour cream can spoil if it's not refrigerated, you may wonder if the same thing will happen to a cake that contains sour cream. The answer depends on whether the sour cream was cooked into the cake, or if the cake contains filling or frosting that contains sour cream. Once you determine how the sour cream was incorporated, you can make the right storage decision.
Sour Cream Baked Into the Cake
Cover the cake with plastic wrap or aluminum foil, or place it in a covered cake container.
Leave the covered cake for up to two days on a countertop or for up one week in the refrigerator.
Cover the pan tightly with aluminum foil and freeze the cake for up to six months if it isn't frosted, or up to two months if it is frosted. Thaw the cake for serving the next day by allowing it to sit out on the countertop overnight.
Sour Cream Used in Filling or Frosting
Place the cake in a covered cake container to avoid smearing the frosting. If the cake is filled, but not frosted, you can cover it with plastic wrap or aluminum foil.
Put the cake into the refrigerator immediately after filling or frosting it. Remove the cake when you want to serve it.
Return leftover cake to the refrigerator as soon as you finish serving it. Do not allow it to linger at room temperature or you will shorten its shelf life. Keep the cake in the refrigerator for two to three days before discarding any leftovers.