Planet and galaxy cakes are popular for birthday themes including “First Trip Around The Sun” and “Two The Moon” for first and second birthdays. You can do these themes for girls and boys, so it’s a gender-neutral theme that works for everyone, or you can use traditional pink and blue.
It’s also really easy to ice a cake using buttercream to create a base that you can add wafer paper or fondant planet and stars decorations to.
This article will go over how to ice an outer space cake using colored buttercream to give you a nice base to work with.
To see some customizable party supplies that I designed to go with these themes, click to see the collection on Zazzle: Planets collection
This article includes affiliate links that will pay a commission if they’re used to purchase something. As an Amazon associate, I earn from qualifying purchases.
You can decorate an outer space cake pretty easily by starting with a white cake and adding some streaky blue icing to give the effect of a dark sky.
In this case, I used one color of blue icing, but you can also mix it up and use two or three to give it some variety. If you make the blue thinner in some spots than in others, though, it works with only one color.
Check out this article that has a comparison of blue food coloring to see which shades you like best for your project: Blue Food Coloring
How to ice the cake.
Start with a white cake that’s iced with buttercream icing. It doesn’t have to be perfectly smooth because the look you’re going for is more uneven than flawless.
Add some dots of blue icing to the cake, using one color or a few colors if you want some variety. They don’t need to be big dots, you can always add more if you need to later.
Smooth the icing onto the cake, not worrying AT ALL about how even the color is. You want to go with uneven coverage because it will give you the impression of a night sky. This doesn’t have to be perfectly smooth so don’t worry about perfection!
If you want to have a darker base icing, start with a dark blue iced cake instead of white, then use lighter blue icing dots on it.
Stop icing the cake when the blue is spread out and the cake looks uneven but covered.
Adding wafer paper decorations.
Add the wafer paper planets and stars to the cake. All that you have to do with wafer paper as long as the icing is still soft is press it onto the buttercream icing.
If the icing has crusted over you can roughen up the icing a little or use some corn syrup on the back of the planets and stars to attach the wafer paper shapes to the icing.
You can also get royal icing or fondant decorations for an outer space cake on Etsy. Click here to see what’s available, and make sure to check the shipping times because some sellers are located internationally, so it will take longer to get the decorations to you.
Again, you don’t need to worry about whether the icing is perfectly smooth, this isn’t a prissy cake design! Have some fun with it and don’t worry that it has to be flawless. The uneven icing will give it a nicer look than having it completely smooth and the same color all over.
Using fondant decorations.
You can buy or make fondant planet cake decorations to put on your cake.
You can marble fondant to use for planets that have a swirled color effect on them. Read this article for tips on making marbled fondant.
When you’re marbling fondant for planets, use bright colors that complement each other, like blue + green or red + orange.
Roll the marbled fondant into balls to use on the top of the cake as planet toppers. You can make them in different sizes and put them on the top of the cake, or arrange them in a pattern like they’re orbiting the sun.
You can also roll out the marbled fondant and cut out round shapes to place on the sides of the cake. If you let them dry flat for a few days beforehand, you can also put them on the side of the cake so that they stand up off of the cake itself.
Click here to see an article about party supplies that coordinate with planet birthday themes.
