A Not So Daily Dose of Daisy
Master of living a random, unpredictable life.
Rainbow Cake In A Jar

I have been inspired… AGAIN to make something that I saw on Pinterest. Both times I have made the rainbow cupcakes they haven’t turned out as bright colored as I wanted them to so I am going to try a different method. Rainbow Cake in a jar! Sounds good already, right?

If I did this project again I would do it in a different order but I will show you in the exact order that we made it for this post.

I have showed you The World’s Best Homemade Frosting In The World in a previous post. It is a creamy white icing that looks and feels like whipped cream.

To make it you need:

  • 1 Cup Milk
  • 2 Tablespoons Flour
  • 1 Cup Butter (softened)
  • 1 Cup White Sugar
  • 1 Teaspoon Vanilla Extract


Whisk milk into flour in a small saucepan until smooth. When I say small, I mean small, it takes up very little room and will probably work faster if you use the smallest pan possible.

Turn the heat on low and start whisking (is that even a word). You will whisk until your arm feels like it is gonna fall off. Eventually it will start to boil. See the bubbles?

Once you see the bubbles remove it from the heat and let it sit to cool. You need to make sure it cools completely before moving on to the next step. If you don’t let it cool completely it will turn your next step into a nasty gooey mess. You could probably put it in the fridge to cool it down faster but I didn’t.

While your waiting for it to cool put the butter, sugar and vanilla in your KitchenAid mixer and beat until it is light and fluffy.

Once it fluffs up add the thickened milk mixture.

Turn your mixer on med-high and beat it until it resembles whipped cream. Mine took about 5 minutes of mixing on the med-high speed. Then removed it and put it in the fridge (you don’t have to refrigerate it right away but I like icing to be cold).

Rainbow Cake In A Jar is the coolest desert I have ever made. This is how I did it:

  • 1 Box of White Cake Mix made per the instructions on the box.
  • Food Coloring
  • 4 One Pint Canning Jars
  • Frosting (see above)
  • Rainbow Sprinkles


Preheat your oven to 350°.

Mix your cake mix exactly like the directions say. Please be sure that you use only the egg whites,  not the yolks… I have made that mistake before!

I also learned that if you are mixing cake mix make sure that you have your KitchenAid mixer handy. I couldn’t use mine because I was still in the process of making the frosting. Big mistake… I truly feel sorry for anyone who does not have a mixer and has to mix by hand. I actually complained about it and JP asked if I need a second mixer… he loves to tease me!

Once the cake mix is ready separate it into 5 different little mixing bowls (or as many colors as you are going to make). Use your food coloring to make your desired colors. Pretty, right?

Next you will need to spray down your jars with baking spray. Be very generous with the spray.

Next you need to add the cake mixture to the jars. Use a spoon… and take your time. You will need to push the colors around a little bit inside the jar.. without mixing them together. Make sure you push it up against the side of the jar so you can see all of the colors. It takes some patients so be prepared. Ours looked like this.

Take your jars and place them in a baking pan. You need to add water to the pan to make this work. Be sure to use boiling water because I have read that if you use cold water it won’t work as well. The original instructions I read said to fill the pan about ¼ of an inch but I went about ½ of an inch and it worked out really well.

The directions on my box said to bake for 30 minutes but when the timer went off they were not done yet. I ended up baking them for about 5 ½ extra minutes. A lot happened in that 5 extra minutes so be sure to keep your eye on it. Depending on your elevation you will need to adjust the baking time. If you are at a higher elevation it will bake faster.

And now the moment we have all been waiting for!!! As soon as I pulled them out of the oven Lily was speechless. She said something about this being the coolest thing she has ever seen.

The cake is going to start to shrink down a little after you take it out of the oven. I am not sure what the scientific reason is, but it will happen so put the lids on right away.

We decided that these are little jars of happiness! How can you not be happy when you look at them?

Once you are ready to eat them pop off the lid, add your icing and some sprinkles… everyone’s face will light up!

As soon as you scoop out a bite the inside of the jar looks cool too!

You can even swirl it around a little if you want to.

A couple notes:

  • The original recipe said to use 3 jars… I used 4.
  • The original recipe had the tall slender 1 pint jars. I used the short fat ones because that is all they sold at my store. I think the short fat ones worked out better.
  • I used neon food coloring
  • The glass is very HOT when you pull it out of the oven. I have a small burn to prove it.
  • When I do this again I will make the frosting after using the KitchenAid to mix my cake mix.
  • If you put the lid on right away the cake should be good for at least a week after you make it. If you do this don’t add the icing until you are going to eat it.
  • You might want to make a pot of coffee to go along with it.
  • You will be the coolest person in your house for at least a few hours after making this dessert.






2 Comments to “Rainbow Cake In A Jar”

  1. […] Today I made the world’s best frosting in the world and I have to share it with you guys. Earlier I told you about making rainbow cupcakes so I needed something to top them with. You can find the actual recipe HERE. […]

  2. CoreyJo says:

    So cool! Can’t wait to try this, and your frosting.

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