Rainbow Chocolate Cake

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Nothing beats a decadent rainbow chocolate cake to celebrate any special occasion with your loved ones. I make it with cocoa powder, rich dark chocolate ganache, and vibrant food coloring to create a stunning layered dessert. This colorful creation is loved by both kids and adults alike.

Layered chocolate cakes have always had a very special place in my heart, whereas my kids adore the vanilla rainbow variety. Unlike my equally decadent chocolate mango cake, the layers here are hidden and unexpected. The deep cocoa flavor balances the sweetness of the frosting, which can be tricky when it comes to cakes.

I first created this cake when my kids could not decide between a vanilla rainbow sponge or my chocolate walnut cake. Why not have both? I aimed for that signature chocolate cake flavor, with the bright and cheerful colors incorporated. Of course, my kids could not fathom how a cake could be both rainbow and chocolate. But boy, were they surprised and impressed! 

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🥘 Ingredients

This cake looks fancy, but I made sure to keep the ingredients simple. I use pantry staples to build these rich layers. 

For The Cake

Almond milk: I use this as the base liquid to keep the crumb soft and moist.

Brown sugar: I add this for deep caramel notes that complement the cocoa.

Coconut sugar: This rounds out the sweetness, which I love.

Salt: A small amount of salt sharpens the chocolate flavor and removes any bitterness from the coffee.

Baking soda: I rely on baking soda for the initial lift when baking.

Baking and cocoa powder: Both ingredients are key to make this recipe.

All-purpose flour: I use all-purpose flour to ensure structural stability within my layers.

Light-flavored olive oil: A mild-flavored olive oil adds to the moisture and keeps my cake from drying out. 

Vanilla extract: For all things chocolate I love a bit of vanilla to bring all the flavors together.

Eggs: I use eggs to bind the batter and add another level of richness.

Dried instant coffee: Like vanilla, dried instant coffee is so well-suited to any chocolate dish, adding a dimension to the flavor. 

For The Buttercream

Egg whites: I always use pasteurized egg whites for a light, structured frosting.

Powdered sugar: This blends seamlessly into my frosting and adds sweetness.

Butter: Softened butter is the main event in all my buttercream frostings

Vanilla extract: I use vanilla extract to add a roundness and counteract any obvious buttery flavor, not suited to sweet dishes. 

Food coloring: I use bright colors to create my rainbow layers.

For The Ganache

Dark chocolate: Finely chopped dark chocolate is ideal for melting and is not too sweet, adding another layer of balance.

Heavy cream: This transforms my melted chocolate into smooth, spreadable, glossy ganache. 

🔪 How To Make

I prepare this cake, step by step, to ensure an organized, baking, and assembly process.

Preheat and prepare: I preheat my oven to 350F, and line my cake tins with parchment paper. Then I whisk my almond milk and lemon juice, and let it sit briefly.

Whisk dry ingredients: In a separate bowl,l I whisk the brown sugar, coconut sugar, salt, baking soda, baking powder, cocoa powder, and flour until fully combined.

Add remaining wet ingredients and combine: I add the oil, vanilla, and eggs to the milk mixture and whisk. Next, I pour the wet ingredients into the dry mixture and stir until just combined.

Make instant coffee: Then I dissolve my instant coffee into boiling water, and stir it into the batter until incorporated.

Divide batter and bake: I divide the batter between the pans and bake for 35 to 45 minutes, or until a skewer comes out clean.

Allow to cool: I let the cakes cool in pans for a minute, then transfer them to a wire cooling rack.

Prepare buttercream: While the cakes are cooling, I whip my pasteurized egg whites with powdered sugar for about 3 minutes.

Add butter: Then I add the butter in 2 stages, and whip until smooth. I add my vanilla extract at the end.

Slice cakes: I slice each cooled cake horizontally into three even layers.

Add food coloring: Next, I divide my buttercream into five bowls and mix in the food coloring.

Add buttercream to cake: I layer cake and buttercream on a cake board, stacking in the ROYGBIV rainbow order.

Prepare ganache, and ice the cake: I heat cream, and pour it over chopped dark chocolate and stir until smooth. I allow it to chill briefly before spreading it over the cake and decorating with sprinkles.

📖 Variations

This recipe may seem extremely specific, but I was surprised by how much I was able to play around with it. These are a few of my favorite variations.

Chocolate orange boost: I add one teaspoon of orange zest to my batter. I love the way the citrus plays off the chocolate flavor. This is a favorite among my older friends and family.

White chocolate swap: If I really want to surprise people, I can cause a bit of confusion by covering the cake in a white chocolate ganache. I personally think this would be amazing as a fun wedding cake.

Ombre rainbow: I know it says rainbow, but I like to break the rules sometimes. I have made layers of one color, varying in intensity, for a gender reveal, and it was gorgeous. 

🍽 Serving Suggestions

I prefer serving this rainbow chocolate cake at room temperature; this way, the layers are not cold to the touch, and the ganache is soft. This cake is extremely indulgent, so when I serve it I always make sure to have a tray of my gluten free brownies so that everyone gets a taste of the chocolate, no matter what their dietary preferences. 

I always feel quite thirsty after having cake, especially chocolate cake. And I rarely have cake without a cold glass of milk to wash it down. This is something I’ve passed on to my kids. With this particular recipe, I like to pair it with my vegan horchata. This way, I can make sure that the flavors complement the dessert, it is dairy-free, and has some added health benefits thanks to the cinnamon. Next time you have chocolate cake, you must try this combo! 

🧊 Storing And ♨️ Reheating

Refrigeration: I store leftover slices in an airtight container in the refrigerator for up to 5 days. I allow the slices to reach room temperature before serving.

Freezing: I wrap individual slices tightly and freeze them for up to 6 months. I then thaw slices in the fridge overnight before serving.

Reheating: I do not reheat this cake, as heat will cause the buttercream and ganache to melt or split. 

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