Gluten Free Rainbow Cake

There's gold at the end of this gluten free rainbow cake! Swiss meringue buttercream and gf velvet cake make this cake as tasty as it is beautiful.

We don't normally do a whole lot for St. Patrick's Day. Sometimes I don't even cook anything Irish. I am part Irish, but I used to not really care for much Irish food. Thank God I grew up and eventually got over that (corned beef is the bomb!). But this year I really felt like going all out because why not? Why should Easter have all the fun? Any time I can celebrate a holiday that involves food, I'm in, haha!

So when I was considering making a cake for St. Paddy's Day, I really wanted to pull out all the stops. And that's exactly what I did! This cake is a monstrosity of a cake, but it's fun and colorful and the perfect cake to serve on the Irish holiday.

I got the idea for this cake from the cake queen, Liz from Sugar Geek Show. She is an extremely talented cake decorator and sculptor and her cakes are AMAZING (check out her Baby Yoda!!). I loved her rainbow cake and wanted to make a gluten free version, so that's what I did. At first I was gonna make a video of me making this cake. But I'm no pro when it comes to cake decorating and Liz is, so you can watch her video here. I kind of made it my own and changed a few things and I'll go over those below.

There are several components to this cake and I'll walk you through each one. But you can also pick and choose your level of cake decorating. The flavor is vanilla in both the cake and frosting so you can just make a lovely vanilla cake. It'll still taste amazing regardless of whether it's decorated or not. You can even halve the amounts so you don't absolutely need to make this ginormous cake! Or you can gild the lily (literally) and go for the gold and make ALL the decorations!

The Components in Gluten Free Rainbow Cake

There are a few components to this cake, but they're all pretty easy. Like I said before, YOU decide how far you want to take it. Here's a list of all the components:

• Cake--I made Liz's cake into a gluten free white velvet cake.
• Frosting--Vanilla Swiss meringue buttercream is the perfect addition to a nice vanilla cake. Feel free to experiment and add flavors if you want (an Irish cream would be great for St. Paddy's Day!).
• White chocolate ganache drip--need I say more? Who doesn't love a thick white chocolate glaze over the top of any cake? Liz makes a thinner white chocolate coating glaze, but I wanted the taste of real white chocolate. Of course if you'd rather make dark chocolate, you can. However, it might need several coats of gold to get it covered completely (more on the gold "paint" later).
• Gold coins--Again, this is something I added to my cake that Liz didn't put on hers. I found these (affiliate link) gold coins on Amazon. They are real milk chocolate.

Make the Cake Layers

This cake, which is a white velvet cake, begins with the reverse creaming method. The dry ingredients and sugar are first mixed together. Then the butter is added and the mixture becomes sandy in texture before adding the liquids. Here's the ingredients you'll need to make this cake:

• Kim's gluten free flour blend--a store bought blend should also work, but hasn't been tested.
• Granulated sugar
• Salt
• Baking powder
• Baking soda
• Egg whites
• Vegetable or canola oil
• Buttermilk--for dairy free, try any of the dairy-free milks plus one tablespoon of vinegar or lemon juice.
• Butter
• Vanilla extract

To make the colors, divide the cake batter between 6 small bowls. To help make them even, weigh each to 15 ounces (or 425 grams). The colors (affiliate link) I used were what Liz recommended for bright and beautiful. These aren't the traditional colors of the rainbow. And I really like the "electric" colors, but feel free to use whatever colors you'd like.

Divide the colors between six 8-inch round baking pans. I don't know about you, but I don't have six so I had to bake three at a time. They'll only be about one inch high, so they don't take too long to bake. The other colors can sit on the counter until the first ones are done.

Make the Swiss Meringue Buttercream

I departed a little bit from Liz's recipe and made Swiss meringue buttercream instead of her easy buttercream. If you've never made Swiss meringue buttercream, it's actually also very easy. But you can also use Liz's easy buttercream, or my American buttercream (without cinnamon) or French buttercream. Here's what you'll need for SMBC:

• Egg whites
• Granulated sugar
• Butter
• Vanilla extract

Measure the egg whites and sugar in your mixing bowl. Place it over a small saucepan with an inch of barely simmering water. Whisk constantly until the sugar has dissolved. To test this, rub a little bit of the mixture between your index finger and thumb. If you feel sugar crystals, it's not ready. You can also indicate when it's done when a thermometer registers 160 degrees F.

Take if off the heat and put it on a stand mixer using the whisk attachment. Whisk on high speed until it reaches firm peaks and has cooled down quite a bit. This will take anywhere from 5-10 minutes, depending on your mixer. Stiff peaks is when you take the whisk out of the egg whites and turn it upside down. If the peaks of the meringue stand straight up, they're at stiff, or firm, peaks.

Add the butter, one chunk at a time, until it's all in the bowl. You may start to notice it look like it's curdled or soupy. This is totally normal. Just keep whipping and it will all come together. Add the vanilla and whisk until smooth. I like to switch to the paddle attachment and run it on low for a few minutes. This will knock out some of the air bubbles that have formed from all that whipping.

The Gold Drip

To make a drip, you'll need to make some white chocolate ganache. Liz uses a water ganache made with candy melts or wafers. I chose to make the traditional ganache using real chopped white chocolate and heavy cream. Chop the chocolate and place it in a microwave safe bowl. Microwave at 30 second intervals, stirring in between, until it's almost melted. Set it aside while you microwave the heavy cream for 20-30 seconds, just until barely simmering. Pour the hot cream over the nearly melted white chocolate and stir until smooth. Set this aside until it cools to barely warm. If you put your finger in it, it shouldn't feel hot or cold, just like your regular body temperature.

I had never done a drip cake before and it's easier than I thought. It's pretty cool how the pressure you use and the length of time you leave it in one spot gives drips of varying sizes and shapes. Fill a pastry bag (or ziptop baggie) with the cooled ganache and snip the end. Hold the bag on the edge of the cake and start putting pressure to let the ganache drip down the side. Release some of the pressure, move the bag, and continue all the way around the cake.

Once you've finished the drip, squeeze the rest of the ganache onto the top. Then use an offset spatula to spread it as evenly as you can. It doesn't need to be perfect because the gold coins will cover the top of the cake (if using). Refrigerate the cake until the ganache is firm, about one hour.

Liz recommends a specific metallic gold paint, but I stuck with this gold edible paint I got at Walmart. It comes with a little paint brush, which is perfect for painting the drips. Squeeze some into a small bowl and paint the drips with the little brush that comes with it. You'll need at least two coats, so let it dry in the fridge in between each coat. This should take no more than 30 minutes.

Piping the Rainbow Swirls and Finishing the Cake

Liz made white buttercream swirls and sprinkled them with some colorful sprinkles. I chose to make mine into rainbow swirls using the rest of my buttercream. Divide the rest of your buttercream into six bowls and tint them the same colors as the cake layers. Use about a quarter of the gel colors that you use for the cake layers. Fill a small pastry bag (or even just a small baggie) with each of the colors.

Pipe about a half-inch stripe of frosting onto a large piece of plastic wrap using the first color. Then continue piping with the rest of the colors, side by side, until you have all the colors in a row. Fold one side of the frosting to meet the other side using the plastic wrap, and twist the ends of the plastic wrap. Cut off one end and stick the whole thing, plastic wrap and all, into a decorating bag fitted with a large open star tip (tip 1M), cut side first.

Pipe swirls on top of your cake at the edges. To get them as even as possible, pipe one swirl on one side. Then pipe another swirl directly across from it on the opposite side. That way they'll be pretty even. Stick gold chocolate coins in between each swirl and onto the top of the cake in the middle. You're done and now you get to taste your masterpiece! This is the best vanilla cake I've ever had, gluten free or not. And the frosting is silky smooth and delicious and marries so well with the cake! You'll have the luck o' the Irish with ya as you dig in!!

I hope you get a chance to make this cake to its fullest potential and admire your handiwork of colorful slices and gold drips!

Recipe and techniques adapted from Liz at Sugar Geek Show