Rainbow Cake in a Jar

Cute rainbow cake in a jar with buttercream frosting and sprinkles. We saw this picture on Instagram and looked up a recipe to try it. We found several recipes and decided to try it in 1/2 pint jars. This makes a large one serving size with a total of 5-6 rainbow cakes in a jar per recipe. This brightly colored cake idea will be fun to eat at any party. It does take some time but the results are worth the extra effort! Use neon or pastel colors to match your theme. Download our version of the recipe here: Rainbow Cake Recipe

Ingredients

1 box of white cake mix. We used Betty Crocker for this recipe but I believe any box mix or your own favorite recipe will work fine.
Buttercream Frosting is our favorite. See our recipe Here or a store bought frosting.
Rainbow Sprinkles or find ones that match your cake colors.
We used Wilton Icing Colors which are very vibrant and you can adjust the deepness of the colors easily. This box will easily last you several years.
Ingredients for the cake mix (usually egg, water and oil)
Skewer or a longer toothpick works best for testing doneness.

Materials

5 1/2 pint sized Mason Jars washed and dried thoroughly.
Pam or Bakers spray
Butter knife or toothpicks for adding color. With gel colors it takes very little to add color so we used toothpicks. The consistency of the Wilton colors make it easy.
6 bowls or however many different colors you choose to use.
Tablespoon measuring spoon

Steps to Make Rainbow Cake in a Jar

Mix cake batter as directed on box.
Pour about 3/4 cup batter into each dish.
Add dye and mix thoroughly. Add more dye if you want colors to be more vibrant.
Spray Baking Spray into each of the mason jars.
Pour about 1.5 tablespoons of each color to fill about 1/2 full. You will be able to fill 6 jars and will probably not have to remove the top to add the frosting as we did.
We started with purple followed by blue, green, orange, yellow and pink.
Wipe excess batter around the top of the inside of the jar.
Bake as directed for 30-35 minutes until center is cooked. Check by sticking a skewer into the jar and checking to see if it comes out clean. If there are cake crumbs on it, bake for another 3 minutes and check again. Each oven may vary and altitude may also need to be factored in.
When completely cooled, add frosting. We love homemade buttercream frosting but you can buy a tub of Buttercream frosting from your favorite brand.
Add sprinkles if desired.

Layering your colored batter to make rainbow cake in a jar.

Over Filling Will Result in Rising

We filled each jar with 2 Tablespoons of each color which resulted in filling the jar as shown above, about 3/4th full. We used two tablespoons which resulted in filling the jar 3/4 of the way. We filled only 5 mason jars with enough batter.

We removed the top of the cake until it was just below the rim of the mason jar.

Tips and Suggestions

We liked the Wilton colors because they have a nice variety and we didn't have to mix colors to achieve any of the colors.
Neon would be a fun palette of colors to try.
We started using a toothpick to add color as the box instructed but we wanted vibrant colors so we used the tip of a plastic butter knife to add the dye to the batter.
Bringing it to a party? Cover with the lid and frost when you get there.
I found the mason jars at Target. The Wilton food dye was purchased at WalMart but they also have them at craft stores like Michaels or on Amazon.

Other Rainbow Cake Ideas

Make a rainbow cake using the same method as above by mixing each color into a bowl. Layer each color by pouring into a prepared cake pan. You do NOT need to mix or swirl the colors because it will automatically do this as you bake. In fact if you mix the colors it make not be as defined in the end result.

Note: You must use a jar that is made of tempered glass which means that the jar that can withstand temperatures up to about 250 degrees Celsius (482 degrees Fahrenheit). However, you should still use caution when using them for cooking or canning purposes. Avoid putting hot liquids in the jar or exposing them to sudden changes in temperature. If a Mason jar is heated too quickly, such as by being placed in boiling water, it can break. The sudden change in temperature causes the glass to expand too quickly and shatter. To avoid this, always place Mason jars in hot water gradually so that the glass has time to adjust to the new temperature. Another way that Mason jars can break is the opposite, by being exposed to extreme cold temperatures. If a jar is stored in a very cold environment, such as a freezer, and then brought into a warmer room or outdoors, the sudden change in temperature can cause the glass to crack or shatter. As a general rule, Mason jars are great for baking. You can use them to make individual portions of cakes, cookies, or even mini pies. Just be sure to leave enough space at the top of the jar so that your baked goods have room to rise.