About One Week
Nationwide ice cream cake producer Carvel recommends you do not store ice cream cake in the freezer or refrigerator for longer than seven days. Ice crystals form in the ice cream and degrade its quality within a week.
It Depends on Your Freezer
Ice cream cake might keep longer than a week, depending on the quality and temperature of your freezer, but when ice crystals form in the ice cream, it is time to throw it out. If you freeze ice cream cake made without cream cheese, butter cream, whipped cream or eggs, it can stay good for up to two months, according to PastryWiz.com.
If you want to eat leftover ice cream cake, you should eat it as soon as possible after freezing it, preferably within a week. The longer you store ice cream cake in the freezer, the more it loses its flavor and texture.