Cake in a Jar or Mason Jar Cakes are a fun, portable, and customizable dessert, perfect for gifts, parties, and holidays! At room temperature, a birthday cake in a jar will last just a day or two. Refrigerate it and it should last up to four days. Or store it in the freezer for several months right in the jar; this way, you’ll have a thoughtful birthday present at the ready whenever you need one.

Butter, Sugar, Flour, Eggs, Milk, and Baking soda.