Christmas Sweater Sheet Cake Tutorial

Have you ever lost all sense of time and space while working on a cake? That was me with this Christmas sweater sheet cake. I had the best time piping all of the textures, going with the flow, and surprising myself with the outcome. It turned out even better than I imagined! I can’t wait for you to make this one and lose yourself in the process (in the best way, of course). 

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This sweater sheet cake design is so perfect for the holidays, whether you need a dessert table centerpiece for your Christmas party or simply want to impress your loved ones with a beautifully detailed cake. I cannot get over how cute it is between the buttercream pom poms and knit textures. Also, I feel like I need a sweater like this for a real life Holiday party. Comment me a link if you find one! 

Knitted Buttercream Details

At first glance, these sweater cake textures look complicated. I’m happy to report that they’re mostly the same piping technique over and over again, just with different piping tips. The real key to making the knit texture look perfect is to measure out sections on the sheet cake before you start piping. Then, you’ll pipe horizontal lines of overlapping x’s to fill in the spaces. Here’s a quick video that shows you how to pipe the knit details: 

I have always wanted to make buttercream pom poms, so I was thrilled to figure out how to add those as details for this sweater sheet cake. I ended up sticking mini gumdrops onto toothpicks, then using Wilton Cake 233 to pipe the pom pom texture onto them. Here is what they look like before they go on the cake. 

What Kind of Buttercream Can I Use?

For these knit textures, you can use any kind of buttercream you’re most comfortable making and working with as long as it’s easy to color. I chose American Buttercream simply because it’s a great consistency for piping and so easy to achieve a Christmas color palette.

Buttercream Piping Tips for Success

This sweater cake design requires a fair amount of continuous piping. That said, I would still consider it beginner-friendly as long as you’re okay that it’s a little tedious. Here are some things I’d recommend to make it as easy as possible:

• Make sure your buttercream is the right consistency. It’s important that your buttercream is at least medium-consistency so that it will hold its shape when piped. Here’s a blog post that details how to ensure your buttercream is the perfect consistency for piping. 
• Practice on a cookie sheet. If you’re not super confident in your ability to pipe directly onto the cake just yet, don’t worry! You can always practice on a cookie sheet or other flat surface to get the technique down before you commit to the actual cake. 
• Mark out sections. This sweater cake design looks best when the lines are even, so before you do any piping, be sure to mark out sections on the frosted sheet cake to use as a guide for your piping. I found that using a cake comb like the one in the middle in this collection helped me create precise sections so that I could stay inside the lines, even with the smallest knit textures. 
• Keep the buttercream from getting too warm. If at any point you feel like the buttercream is getting too warm while piping, there are a few things you can do. First, you can place the bag in the refrigerator for about 10 minutes to let the frosting firm back up slightly, then gently massage it back into a uniform consistency for piping. Second, you can run your hands under cold water to keep them nice and cool. Buttercream usually gets too warm from too much handling of the bag. 

Christmas Sheet Cake Recipes

Before you can get started with decorating, you’ll need a baked and cooled sheet cake for this tutorial. You can certainly use your go-to sheet cake recipe or enough boxed cake mix for a 9 x 13 inch cake pan, or bake any of my layer cake recipes as a sheet cake! Here are some sheet cake flavors I’d recommend for this cake design: 

• Vanilla Sheet Cake
• Gingerbread Latte Sheet Cake
• Pumpkin Sheet Cake
• Spiced Apple Sheet Cake
• Chocolate Sheet Cake
• Funfetti Sheet Cake (but with Christmas sprinkles)
• Red Velvet Cake Recipe
• Peppermint Hot Cocoa Cake
• Eggnog Cake
• Peppermint Mocha Cake

If you’re using any of the above layer cake recipes, just make the recipe for the batter as-is, grease and line a 9×13 inch baking dish, fill it with the batter, then bake in a 325ºF (163ºC) oven for 30-35 minutes, or until a toothpick inserted comes out clean.

You Will Need

• A baked 9×13 inch sheet cake
• 5-6 Cups of frosting (I used a double batch of my vanilla buttercream recipe)
• Red and green food color gel
• Icing spatula
• Icing smoother
• Icing comb with square teeth like this OR a ruler
• Wilton tips: 4B, 32, 3, 10, and 233 (x2) 
• Piping bags 
• 6 mini gumdrops
• 6 toothpicks

Step 1: Mix the Buttercream Colors

Divide the buttercream into three separate bowls. In the first bowl, add red food color gel until you reach your desired color. I used about 10 drops of AmeriColor Super Red for this. In the second bowl, add green food color gel until you reach your desired color. I used about 6 drops of AmeriColor Forest Green for this deep green color. Keep the last bowl uncolored (white) and keep in mind that the red and green colors will darken over time. 

Step 2: Prepare the Piping Bags

Fit one piping bag with Wilton Tip 3 and add about ⅓ of the white buttercream, then set the rest aside for frosting the cake. Fit one piping bag with Wilton Tip 4B and fill it with ¾ of the red buttercream, then divide the rest of the red buttercream between two other piping bags, one fitted with Wilton Tip 233 and one fitted with Wilton Tip 10. 

Add ⅓ of the green buttercream into a piping bag fitted with Wilton Tip 233 and add the rest of the green buttercream into a piping bag fitted with Wilton Tip 32. 

Step 3: Make the Buttercream Pom Poms 

Stick one of the mini gumdrops onto a toothpick, then choose one of the red or green piping bags fitted with Wilton Tip 233 to pipe pom pom texture (aka shag texture) all over the surface of the gumdrop. When you’re finished piping, stick the toothpick into a styrofoam block, cardboard box, or something else that will keep it upright. 

One by one, continue the process of making buttercream pom poms until you have 3 red ones and 3 green ones. Then, refrigerate the pom poms until they’re easy to handle without ruining the piping (about 20-30 minutes).

Step 4: Frost the Sheet Cake 

While the buttercream pom poms are in the refrigerator, use the reserved white buttercream to frost a thin, smooth layer of buttercream onto the cake. I used my icing spatula to spread the buttercream on, then used an icing smoother to level it out. The buttercream will be covered by piping, so don’t worry about being a perfectionist with the finish. 

When you’ve got a level layer of buttercream on your cake, refrigerate it for 15-20 minutes to let the frosting firm up before you move on. 

Step 5: Measure the Piping Segments 

In order to pipe perfect horizontal lines, you’ll need to make yourself a piping guide. You can get creative with how you do that, but what works for me is using an icing comb with square teeth. I waited until the frosting on the sheet cake was nice and firm, then dragged my icing comb across the surface to create perfectly spaced horizontal lines. 

I had already drawn a picture of what I wanted the final cake to look like, so I counted out the horizontal lines and used the blade of my icing smoother to really mark out where each section would begin and end. Here’s what it looked like before I started piping. 

Step 6: Pipe the Knit Textures 

Now comes the fun part – piping! I started in the middle section with my red buttercream and Wilton Tip 4B, essentially piping a series of overlapping x’s to create a braided look for the center section. 

Next, I used the white buttercream with Wilton Tip 3 to pipe four lines of knitted texture beneath the red center section. Since I used the icing comb to mark the horizontal sections, I was able to just pipe within each line that the icing comb created. 

Repeat four lines of that same knitted texture above the red center section.

Use the green buttercream with Wilton Tip 32 to pipe a mini version of the braided buttercream beneath (and above) the white knitted sections. 

Then, repeat three lines of the white knitted texture beneath and above the green sections.

Next to the latest sets of white knitted texture, add a border of dots using the red buttercream and Wilton Tip 10. 

Step 7: Place the Buttercream Pom Poms

Grab the buttercream pom poms out of the refrigerator and one by one, carefully remove the toothpick and place them onto the sections of white knitted buttercream that have four lines. Since the buttercream is cold, they should be much easier to handle without messing up all your pretty pom pom texture.

Finally, add a simple shell border on the very bottom and top edge of the sheet cake using the green buttercream and Wilton Tip 32. I left a little blank (white) space between the red dot borders. 

And voila! The cutest Christmas sweater sheet cake ever. I am so happy with how this design turned out and cannot wait for you to try it! 

Let me know if you use this tutorial to make something special for the holidays. Feel free to leave a comment below letting me know how it went or tag me on Instagram to show me a photo! I love to see what you create.