How to Make a Simple Chocolate Rainbow Petal Cake

Rich & moist chocolate cake covered in the fluffiest vanilla buttercream colored in vibrant rainbow colors! A perfect chocolate cake for a special birthday cake or party or for yourself on the weekend like I tend to do during Pride.Subscribe

Be sure to grab the full recipe & check out the full video tutorial in the recipe card below. And if you try this recipe (I mean you totally should be), tag me on Instagram @imancake and use the hashtag #BakingWithMANCAKE.

TIPS FOR THE PERFECT BAKE

HOW DO YOU MAKE A SIMPLE CHOCOLATE CAKE?

Sift and whisk dry ingredients together.
Mix wet ingredients in a separate bowl.
Add wet to dry mixture and mix until combined.
Bake in prepared pans until centers are springy to the touch.

Use Room Temperature Ingredients

Cold ingredients do not mix well with room temperature ingredients. As with any recipe that calls for dairy products, always be sure to take the time to bring ingredients to room temperature because it will result in a lighter, fluffier bake.

Proper Measurements

Proper measuring of ingredients is key to perfectly baked cakes & cupcakes, especially when you are making them from scratch. Take a moment to kneel down, get face to face with your measuring cup, and measure liquids at eye level in standard liquid measuring cups.

When it comes to dry ingredients, measure by spooning the ingredient into a measuring cup or spoon, then leveling off the top with a knife or straight edge spatula.

Don’t Overmix the Batter

No matter what you will be placing into your oven, over-mixing the batter can lead to over-developing the gluten, which means your cake or cupcakes will come out dense and heavy.

Bake Immediately

Bake your desserts immediately after mixing the batter. Letting batter stand for too long can cause some of the air you’ve beaten in to escape, making for a denser bake.

No Peeking!

While it can be tempting, resist the urge to peek in the oven on your dessert’s progress. Opening or closing the oven door before the baking time is complete can cause fragile air bubbles in the batter to burst, preventing the bakes from rising. Even if you are gentle with the oven door, a rush of cold air can affect the bake while it is trying to set up, resulting in dense, deflated bake. Try to resist the urge to peek until your bakes are at least 2/3 through their baking time.

How to Test if Your Baked Treats are Done

Test your bakes for doneness while they’re still in the oven by inserting a cake tester or wooden toothpick into the center. Your bakes are done when the tester or toothpick comes out with no more than a few moist crumbs clinging to it; you should see no wet batter. You can also gently press down on the bake and, if it bounces back leaving no dent, then it is done. If removed too early, the bake will sink in the center as it cools and, if over baked, it will be dry.

SOME TIPS TO MAKE THE PERFECT CAKE

WHAT MAKES THE CAKE MOIST AND FLUFFY?

Adding the right amount of fat gives chocolate cake a moist crumb. Fluffiness comes from using the right amount of leavening agent; too much and the cake will collapse, too little and it will be dense.
Another way to get a moist and fluffy crumb? Creaming the butter and sugar coupled with whipping egg whites until they reach the soft peak stage then folding them into the batter.

HOW DO YOU MAKE A CHOCOLATE CAKE MOIST FROM SCRATCH?

Use a nice quality cocoa powder, fresh ingredients and remember to balance the sweetness with a bit of salt. Follow the recipe below for the most moist and fluffy chocolate cake imaginable.

Don’t over bake your layers! Watch the batter and remove from oven when the centers spring back when pressed lightly and the edge starts pulling away from the pan.

WHY DO PEOPLE PUT COFFEE IN CHOCOLATE CAKE?

Coffee brings out and amplifies the chocolate flavor in baked goods like cake and cupcakes. Adding a little bit will make things taste more “chocolatey” without giving a coffee flavor. Adding a LOT of coffee will create a mocha flavor. If you would like to omit the coffee from this recipe just substitute for warm water or milk. I’ve done this and the cake still tastes great! Just a little toned down in my opinion.

WHAT’S THE BEST FROSTING FOR CHOCOLATE CAKE?

I love a chocolate American buttercream. The cocoa powder and bittersweet chocolate along with a nice dose of salt really balances out the sugar and creates a decadent flavor explosion!
If you like things less sweet and maybe a bit more subtle then you should try a meringue-based frosting like Swiss or Italian buttercream. The consistency is VERY light and creamy with not too much sugar.

HOW DO YOU MAKE A CHOCOLATE CAKE MOIST FROM SCRATCH?

Use a nice quality cocoa powder, fresh ingredients and remember to balance the sweetness with a bit of salt. Follow the recipe below for the most moist and fluffy chocolate cake imaginable.

Don’t over bake your layers! Watch the batter and remove from oven when the centers spring back when pressed lightly and the edge starts pulling away from the pan.

WHAT KIND OF COCOA POWDER DID YOU USE?

I used Hershey’s Unsweetened Cocoa Powder in order to use a brand that is most widely available to my readers. I’m also fond of using higher quality cocoa powders like Ghiradelli’s or cocoa powders from specialty chocolatier shops, but those are pretty pricey. I don’t recommend using cheap store brands.

INGREDIENT SUBSTITUTIONS

If you are not a coffee fan then sub in milk, or water. The coffee, which you really don’t taste, helps bring the chocolate taste out but I know lots of people either can’t stand it or have dietary restrictions.
If you don’t have sour cream handy then plain whole milk yogurt will work just fine!
Buttermilk can be annoying to keep on hand as it expires quickly and most recipes use very little. I often use powdered buttermilk reconstituted with water or add a tablespoon of lemon juice into some whole milk to curdle it.
I’m OBSESSED with cacao nibs, they’re pure, unprocessed chocolate aka they’re very crunchy and chocolatey but not sweet! They contrast the buttercream nicely and prevent the cake from cloying. DOn’t worry if you can’t find them, you can totally skip them, or sub in chopped nuts. Use your favorite nut and never forget to toast them!!
If you don’t like coffee just use water or milk instead. Both will still make a tasty cake

Cake Troubleshooting

Why are the Baking Pans Sticking to the Cake?

While spring form pans make it easy to get the cakes out of the pan with minimal cleanup, they can sometimes stick to the cake. A high sugar content recipe can cause the batter to caramelize against the baking pan, and a lower fat recipe tends to stick more than a batter higher in fat.

If you notice your cakes are sticking to the baking pans, try placing a deep baking pan filled with water on the bottom rack of your oven. This added moisture my help prevent sticking. A cake is also more likely to stick to the baking pan if it has not cooled completely before trying to unwrap it.

How to Store Cakes

Cakes are at their best within the first 2 days of baking. While they can last up to 5 days at room temperature in an airtight container, they will start to dry out after 3-4 days.

Be sure to let the cakes cool completely. Packing un-iced cakes while still warm can create sticky tops, making it more difficult to get the icing to stick when you are ready to frost them.

Choose an airtight container that is tall enough, so the container lid doesn’t touch the icing. Typically, the container can be left out at room temperature; however, if you are experiencing hot and humid weather that is causing the icing to melt or if the cakes are filled or decorated with something that requires refrigeration (like lemon curd or a meringue buttercream), you can store them in the refrigerator. If you must refrigerate your cakes, bring them back to room temperature before serving.

Freezing Baked Cakes

Un-iced cakes can be frozen for up to 3 months. Be sure the cakes are completely cooled to room temperature before freezing to avoid condensation forming, which can result in soggy cakes when it’s time to defrost them.

While simply placing the cakes in an airtight container is enough, individually wrapping each cake before placing them in the airtight container will better help preserve the freshness and taste. After removing them from the freezer, let them defrost uncovered to prevent the tops from getting sticky.

The Recipe

Ingredients

1 ½ sticks butter at room temperature
1 ¾ cups white sugar
2 cups all-purpose flour
¾ cup cocoa powder
1 ¼ teaspoon baking soda
½ teaspoon salt
2 eggs at room temperature
1 teaspoon vanilla extract
1 1/3 cup warm water or fresh brewed coffee
1 stick butter at room temperature
1/2 cup vegetable shortening
1 teaspoon vanilla
4 cups powdered sugar, sifted
4 tablespoons heavy cream at room temperature
Food gel color (red, orange, yellow, green, blue, purple)

Instructions

Preheat oven to 350 degrees.

Chocolate Cake

Cream together butter and sugar until light and fluffy on a medium speed for about 2 minutes.
Add eggs and vanilla.
Beat butter mixture at a medium speed for about 1 minute.
In a separate bowl, whisk together flour, cocoa powder, baking soda, and salt.
Slowly add the dry ingredients to the butter mixture while alternating with water. Be sure to start and end with the dry ingredient mix.
On a low speed, mix until creamy. You should not need to mix longer than a minute at most. With that said, be sure not to over mix.
Pour cake batter into a prepared pan.
Bake for 40 minutes or until a cake tester comes out clean.
Let cool for 10 minutes in pan. After, invert onto cooling rack and let cook entirely.

Vanilla Buttercream

Sift 4 cups of powdered sugar & set bowl aside.
Cream butter & shortening.
Add vanilla.
Scrape down the sides.
Place your mixer on the lowest speed & slowly add in your powdered sugar, 1/2 cup at a time.
Do not worry if your buttercream looks crumbly & dry because we will fix that next.
Scrape down the sides one last time.
With your mixer on a medium high speed, slowly add in heavy cream.
Turn mixer up to a high speed and whip your buttercream until you have light & fluffy consistency you are looking for.
Divide buttercream evenly between 6 bowls. Leave one bowl white for the clouds.
Use gel food coloring (red, orange, yellow, green, blue, purple) to color each bowl of buttercream to your desired vibrancy. Whisk in food coloring until evenly blended.

Decorating

After your cakes have cooled, level your cakes. If you’d like to make this a 4-layer cake, half each cake.
Place your first layer onto your cake turntable.
Spread a generous amount of vanilla buttercream on top and spread evenly with your straight or offset spatula.
Place your next layer of cake, top with more buttercream, and spread evenly. If you’re going 4-layers, continue this step until you’ve topped your cake stack with your last layer.
Starting from the bottom, and while rotating your cake turntable, pipe on your vanilla buttercream in an upward motion.
Using a cake frosting scraper, straight spatula, or offset spatula you will want to smooth over your vanilla buttercream. The best way is to hold your smoothing tool upright and gently pressed against your cake while rotating your cake turntable.
You’ll want to continue this until you have a smooth coating. When you’re doing the final smoothing and you notice the texture of the buttercream become a bit ragged there’s an easy fix! Get a bowl of HOT water and dip your tools into the bowl to warm them up. pat dry and smooth. The warm metal will melt the buttercream and give you a nice SMOOTH finish.
Smooth the top of your cake with an offset spatula.
Set in the fridge and allow to chill for 5 minutes.
Next, you’ll want to pipe on your rows of buttercream petals. If you’re using 4 layers of cake, you’ll have enough space to give each color two rows.
Pipe on a buttercream dot and swipe up with your piping bag. Then just repeat in a horizontal motion, alternating between your colors after each set of 2 rows.

Notes

Room Temperature Ingredients: Be sure to allow your dairy ingredients to reach room temperature. Room temperature ingredients not only combine more effortlessly (no over-mixing needed) but they also trap air so much better. This trap air will expand and produce a fluffy texture during your baking process.
Prepared Pan: There will always be the “next best way to prepare your pan” article. Simply put however, the most effective way i find in my kitchen is a light rub of shortening around the sides, parchment paper on the bottom of the pan, & a very light dusting of flour (cocoa powder for chocolate baked goods) all throughout.
You can use this buttercream right away or place it in an airtight container in your fridge until ready to use. Just be sure to whip before using.
If you’d prefer to skip the shortening, simply swap it out with 1 additional stick of room temperature butter.
If you’d prefer a more white, stiffer, buttercream then simply omit the butter & replace with 1 additional cup of shortening. Also be sure to swap out the vanilla extract for clear vanilla extract.
Make sure you sift your powdered sugar. This will help the sugar mix into the butter & shortening smoothly.
When all your powdered sugar has been added in, the buttercream will appear dry. Don’t raise the alarms. When adding in your milk or heavy cream, your buttercream will start to have the fluffy texture it‘s known for.
Keep in mind that your heavy cream should be added in 1 tablespoon at a time. I do this way to make sure I am not drowning my buttercream to the point of a soupy mess.
Also worth mentioning, if desired, you can easily swap out the heavy cream for equal parts of your preferred milk such as whole milk or buttermilk.
If you prefer, you can always buy white fondant only, portion it out, and color with food gel color.