Cover a cake with an all-over shell design! This Purple Shell Cake is simply one motion repeated over the entire cake. So simple. So pretty!

Simple, fast, and so easy to personalize!

I had some purple frosting left over from my Purple Ombre Messy Ruffle Cake so decided to try something different. A “clean” ruffle! This cake is basically the same as the messy ruffle only a bit more precise and organized. (I originally shared this design in 2013 on my Perfect White Cake, just in case you want to see it in a different color)

To make this cake you will need:

white cake recipe (I used a box mix for this cake, it was 4 cups of batter so I put 1 1/3 cup batter into each  cake pan)

8-inch round cake pans

buttercream recipe

food color for buttercream (I used the formula for “pretty purple” and “deep purple”)

extra confectioners’ sugar (if your frosting gets too creamy)

pastry bags (I double bag all my frosting and you can see that here)

#21 tip (can also use a #18)

Purple Shell Cake

I had to use SO much food color to achieve the deep, rich purple that I changed the integrity of my frosting. It was so soft and creamy that it did not want to hold that messy ruffle, so I had to go back and add a bit more confectioners sugar. This helped the frosting to not droop as much.

I added “extra confectioners sugar” above as a reminder for you. If after you have achieved your desired color the frosting is too creamy, feel free to add some more sugar to stiffen it up. I would start with 1/4 cup at a time.

You can also chill the frosting for 5 minutes in the freezer.

PRO TIP: Frosting will DARKEN over time.

Add your food color until you are close to the color you are trying to match but not quite there… then let it sit for 10 minutes. You will see that the color has deepened!

Tools for Cake Decorating

(In the video below I show how I created the lines around my cake in case you are a visual person)

To get somewhat even lines around my cake I used this handy dandy scraper. I use this ALL THE TIME and for so many things, but mainly for creating a smooth, clean edge of the cake. It happens to have a ruler on the side so I held it up to the side of my cake and created a mark every inch with the toothpick.

I then went back and make a line on the side of the cake with the scraper itself.

I also drew a line around the center of the cake with the toothpick (just freehand).

The round (kinda) cookie cutter was used to create a guideline on the top of my cake where I added some of the dark purple frosting.

Decorating Tips

I just want to show you the #21 tip. These are all the same tip shown just how they arrived. As you can see, there are some big differences! Some a closed, some open, some bent. This WILL produce different looks, so what should you do?

I recommend trying to bend the tines in with the back of a spoon for a more closed look. If you want the stars to be more open (like on the 3rd tip) you can put the end of a wooden spoon up into the tip and gently press out.

I chose the 2nd tip, or the slightly closed tip, to make this cake.

(FYI: You can see more of my decorator’s tips here.)

Here is a video on how to made this cake: (this one is long but I have a 15-second version on Instagram!)

As you can see this cake goes quickly, is easy to master, and is quite pretty to look at! (If I am allowed to say that about my own cake!)

Simple, fast, and so easy to personalize!

I couldn’t stop taking pictures of it… the way the light hit those little groves of frosting was mesmerizing.

Actually, just decorating this cake was an experience in relaxation. 🙂

If you like this cake be sure to check out my other decorated cakes here!

Simple, fast, and so easy to personalize!

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Meet Amanda Rettke

Amanda Rettke is the creator of I Am Baker, and the bestselling author of Surprise Inside Cakes: Amazing Cakes for Every Occasion – With a Little Something Extra Inside.Over the course of her 15+ year blogging adventure, she has been featured in and collaborated with the Food Network, New York Times, LA Times, Country Living Magazine, People Magazine, Epicurious, Brides, Romantic Homes, life:beautiful, Publishers Weekly, The Daily Mail, Star Tribune, The Globe and Mail, DailyCandy, YumSugar, The Knot, The Kitchn, and Parade, to name a few.

Reader Comments

  1. Hi! I’m Maya, I’m 15 and from New Zealand, I really enjoy your blog! I really love this cake, and I love your new website design/layout! I have one question, on the main page, it says “life is what you bake of it”, and I was just wondering if those were lyrics from a song that have been slightly modified. Thank you 🙂

    1. Hi! I am not exactly sure what song you are referring to so I can’t speak to that. It’s just a saying that seemed to really fit me and the blog. Hope that’s ok with you! 🙂

  2. Amazing!! This video is mesmerizing! I also LOVE your new blog layout, Amanda!! 🙂

  3. This cake looks beautiful; I would love a piece right now. I’m definitely going to give this ago as I love the flavor combination.

  4. Hi Amanda, I’m totally impressed by your cake making skills. You’re very creative minded and I just can’t believe how you made that purple shell cake. At first I wasn’t 100% sure that’s a eatable cake. Could you please tell me how long it took you to build that cake? I’m very interested to know

  5. Love the cake. Question. Why do my piping bags always pop open when I’m trying to decorate. I’ve tried 2 different materials and they both broke down the side. I kno it has to be me. Just don’t kno why.

    1. Maybe try for a higher quality bag? Or have your frosting be a little more “loose” or runny than you are used to. 🙂

  6. Thank you for sharing a great information and useful. it really necessary and timely for me at this time. I wanted to share this information with my friends on the social network facebook.Thanks for sharing with us.

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