Marbled buttercream cakes have been popping up here and there for awhile now, but just recently, my Instagram feed has exploded with them, thanks to Delaney’s Desserts cracking the buttercream marbling code. Once I took a look at her tutorial, and found out about her marble collab, I couldn’t resist giving it a try. This is my first dive into the world of Instagram cake collabs, and I was super eager to be a part of such a large group (150+!), all focusing on one technique, but each bringing our own unique perspective to it.
For my own marbled cake, I was inspired by the packaging of the Bonne Maman Secret Garden Jam I had purchased a few weeks prior. A combination of strawberry, raspberry, and elder flower, the jam came in the cutest box jam has ever come in. When I started planning my marbled cake, I decided I would do the marbling technique on the top and sides, but leaving a fault line gap that I would fill in with buttercream strawberries, raspberries, and elder flowers.
I started a week ahead, piping my buttercream strawberries, raspberries, and strawberry leaves. I piped onto wax paper squares on a flower nail, using a Wilton 352 leaf tip for piping the leaves around the berries, and an Ateco 103 petal tip for piping the strawberries. I piped a few leaves in a circle for the base, then used the petal tip to pipe a rosebud shape on top. Then I used my (clean) finger to smooth the buttercream up and over the top of the rosebud to close it off and create a strawberry shape. You could wear gloves for this, if you want to be super sanitary. I finished up by placing some round, white sprinkles onto the strawberry, using tweezers, to replicate seeds.
The raspberries started the same, with a ring of leaves, then I used a Wilton 12 round tip to pipe the basic shape of the raspberry. After that, I used a Wilton 3 round tip to pipe tiny dots all around the raspberry.
The strawberry leaves were piped with the Ateco 103 petal tip. Starting at the base of the leaf, I placed the smaller end of the tip facing me and the wider end angled away and to the left. I moved the tip back and forth, away from me, and towards me, as I slowly moved it in a circle from left to right, creating a wide, rounded leaf. I refrigerated all of the buttercream piping I’d done, so that it would be firm when I went to apply it to the cake.
The cake was a white cake, filled with the Secret Garden Jam and a pistachio pastry cream, and covered with a lemon american buttercream. All of the piping was done using a sweetened condensed milk buttercream flavored with vanilla. The cake is four layers of four inch cakes. I used a white chocolate ganache to create a dam in each layer to hold in the jam and pastry cream. This also seemed to help stabilize the cake when I went to frost it.
After covering the cake with one solid layer of white American buttercream, I refrigerated it overnight. In her tutorial, which you can watch here, Delaney recommends freezing the cake for a short time, but I do not have a big enough freezer for this so I used the fridge and it worked out fine. I just left it in overnight so it would be nice as firm.
Then comes the fun part. I highly recommend watching the video tutorial to see it in action, but I will describe the process, and include some pictures, for my own take on it. I used wax paper because I wanted a little more give, but you can use acetate as well. You want to measure the circumference of your cake, BUT you need to add a bit of length onto that, because adding your marbled layer will actually increase the circumference of your cake. So, if you only did the exact measurement, you would come up short. I added a bit too much extra length, but, you can cut it off once it’s firm, and I’d always rather have too much of something than not enough.
Once you have the length you need, cut a strip of wax paper or acetate the length you decided on. I also cut the width of my strip down because I knew I wanted to do one strip of marbling at the bottom of the cake and one at the top. Then you want to have three bowls in front of you: one with white buttercream, one with your colored buttercream, and one empty. The empty one is the one you’ll mix your colors in. Take a scoop of white and a scoop of color and put them in the empty bowl and swirl them together just a tiny bit. Use an offset spatula to spread them along your strip of wax paper, paying attention to your rough edge to make sure you like the way it looks. You can peek underneath from time to time to see how it’s going, and let me tell you, you will be really impressed with yourself when you realize how cool it looks. I think I may have yelled something like “that’s so cool!” at my first glance. I know, I’m pretty modest. Be sure to only mix a little bit of the frosting at a time, as you go, otherwise it will get muddied.
Once you get to the end, be very careful to make sure the whole strip, end to end and top to bottom, is an equal thickness. You won’t be able to get it perfect, but it’s important to get it as close as you can, so it will adhere to the cake. Then you get your chilled cake out and very carefully pick up your strip and wrap it around the base of the cake, making sure it’s flush with the bottom the whole way around. Smooth it back until the ends meet, then use a fondant smoother, or your hands if you don’t have a fondant smoother, to gently smooth the buttercream wrap and make sure it’s all touching the cake. If you have places where it’s gaping away from the side of the cake, you want to try to push that part in. If you use acetate it will be stiff and difficult to do, if you use wax paper, it can be done, but you’ll get some wrinkling. That’s why it’s so important to have an even layer of marbling. Also, where the ends meet, you want to smooth the excess together and make sure there’s no gap there either.
Now you need to chill it again before removing your wax paper or acetate. I was doing a strip along the top as well, so I repeated the process, then took my cake out and added the strip around the top, and then chilled the whole thing again in the fridge for about twenty minutes. Then I carefully pulled both pieces of wax paper off, and used an X-acto knife to trim off the excess from the ends of the strips, and to trim around the top, so nothing stuck up over the edge.
Now here’s the part I struggled with a bit. I wanted the top to be marbled as well. To do this I followed Delaney’s suggestion to make a circle of marbled buttercream instead of a strip and then apply it to the top of the cake. The process is basically the same as the sides except you want to make it a bit bigger than the top. I traced a circle onto my wax paper, then went beyond it when frosting, but I went a little too far beyond and it was way bigger than I needed. I also made it way too thick. Then I flipped it onto the top of the cake smoothed it a bit with the fondant smoother, and chilled it for twenty minutes. Then, after you peel off the paper, you need to trim your excess. I had A LOT of excess, so trimming it required a little more care. The bigger problem though, was the thickness, because I got a definite thick line at the top of the cake, that didn’t match the sides. So, I would definitely err on the thinner side when doing the top piece. After everything was trimmed I lightly ran my scraper over the top and around the sides just to smooth out any major imperfections. You don’t want to smooth too much, or you’ll change your buttercream marbling.
Once my marbling was done, I painted some gold Edible Art Paint along the edges of my fault line, and then began piping my elder flowers. For the elder flower leaves, I used a Wilton 352 tip, and for the flowers themselves, I used a Wilton 224. After piping the majority of my elder flowers, I started to pipe raspberry leaves and stems onto the cake using an Ateco 66 for the leaves and a Wilton 3 for the stems of both the strawberries and the raspberries. I pulled the strawberry leaves, strawberries, and raspberries out of the fridge and placed them as I went around the cake with my stem and leaf piping. I may have gotten a little carried away with the amount of these I put on the cake. I feel like I covered up my fault line detail a little too much, but I love how cute the berries look, and couldn’t help myself.
The marbling process itself was so much easier than I thought it would be. The little things that bothered me here and there were negligible and were most likely just from it being my first time. Overall, I was really impressed with the results. Again, huge shout out to Delaney of Delaney’s Desserts for putting out this tutorial. I hope my summary of the video is helpful (I like to see things written out sometimes), but all the credit for this technique goes to Delaney. Also, big thanks to her for starting the marbling collab! I’m not sure I ever would have tried this technique without that extra kick in the pants. Be sure to check out #marblebuttercreamcollab on Instagram!