I've been making cakes for the last couple years, however I never knew that you could bake a cake in a jar! I LOVE this idea! Especially this rainbow cake, it's so fun to see all the colors through the glass. One more wonderful idea that you can use a mason jar for! Check out the recipe for the rainbow cake in a jar at The Family Kitchen. The Cupcake in a jar is such a great way to present cupcakes in a fun way, and easy to take on the go! These are from The Cake Plate found on Intimate Weddings.