Rainbow Cake
My middle kiddo has loved rainbows for as long as I can remember, and for her fifth birthday, requested a Rainbow Cake. And after looking online and finding a lot of cakes with rainbow layers, but none that actually looked like a rainbow—which is what she wanted—we came up with this easy method. To make this cake, you simply bake a round cake, and cut it in half. Then you use frosting to sandwich the halves to make your rainbow cake. Best of all? The cake is so fun that it doesn’t even matter if the rainbow colors look perfect…or anything but! This is (for sure) one of my most elaborate recipes, but while there are a bunch of steps, nothing is hard. And the pay off at the end is so worth it!
Ingredients You Need
To make this cake (and the frosting) you’ll need:
Unsalted butter: This allows us to add just a little salt to round out the flavors. Sugar: I use granulated sugar in this cake recipe.Eggs Vanilla extractWhole milk: Have this at room temperature if possible.All-purpose flour: This flour helps the cake stay light and fluffy.Baking powder SaltSprinkles: I like to add nonpareil-style sprinkles to the cake to make it have pops of color!
TIP: Then for the frosting and decorating, you’ll need cCream cheese, powdered sugar, ffood coloring, and marshmallows.
Step-by-Step Instructions
Here’s a look at what you’ll need to do to make this cake. TIP: I usually make the cake the day before I plan to serve this to cut down on how much work I need to do on any one day.
How to Assemble the Cake
Once you have the cake made, you’ll need to make the frosting and put the cake together. Here’s how. Scroll down to the bottom of the post for the full info. TIP: This does not have to be perfect. It’s so fun regardless!
How to Store
This cake is best on the day it’s assembled Cover any leftovers with plastic wrap and store at room temperature for up to 2 days or in the fridge for 3-5.You can bake the cake the day before you plan to serve it. Let it cool fully on the wire rack, then place onto a plate lined with parchment paper and cover tightly with plastic wrap to make sure it stays fresh. (Or line a large airtight container with parchment paper and cover.) Store at room temperature.
Best Tips for Success
I used gel food coloring from Wilton for bright colors. Any will work. (This is a natural option from India Tree.)I like these plant-based food coloring options.I like to add nonpareil-style sprinkles to the cake for a pop of color in each slice.A small cake icing spatula is a good tool for adding the frosting, though a butter knife can also work.Place candles on top for a birthday cake.You may have a little of each frosting color left over.Make the cake chocolate using my Healthy Chocolate Cake recipe.
I’d love to hear your feedback if you try this recipe, so please comment below!
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This post was first published May 2021.
