Add a little fun to your next dessert with this 6-inch Single Layer Funfetti Cake! It is moist, tender, and mixed with a handful of rainbow jimmies! For added vanilla flavor, pair it with this small-batch vanilla flour buttercream and top it with a mix of some of your favorite sprinkles! It's another easy and delicious single-layer cake recipe you'll be sure to love!
Table of Contents
- 8 Reasons to Love This Funfetti Cake
- Let's Talk Ingredients
- Substitutions
- Homemade Cake Flour Substitute
- What is Flour Buttercream?
- How to Make Small Batch Vanilla Flour Buttercream
- Make Your Own Sprinkle Mix
- Single Layer Cake Troubleshooting / FAQs
- Essential Funfetti Cake Making Tools
- More Single Layer Cakes!
8 Reasons to Love This Funfetti Cake
- It's easy to make.
- Yields only 1, 6 inch single layer funfetti cake—but thick enough that it can be sliced into 2 layers!
- Perfect for up to 4 people people (or really even up to 6—if no seconds is cool with everyone).
- It's moist and tender—thanks to the added buttermilk!
- Adding rainbow jimmies (or sprinkles) to your desserts is fun and makes people smile!
- It's paired with a vanilla buttercream that is NOT made with powdered sugar.
- It's wonderful for small dinner parties or birthdays, an intimate dinner, or a really nice way to treat yourself!
- You can make your very own rainbow sprinkle mix for decoration!
Let's Talk Ingredients
To make these moist and tender vanilla funfetti cake, you'll need the following ingredients:
- Cake Flour
- Baking Powder
- Salt
- Unsalted Butter
- Granulated Sugar
- 1 Egg
- Vanilla Extract
- Buttermilk
- Rainbow Jimmies (or sprinkles) + plus more for decoration (see below)
Substitutions
Cake flour substitute. If you do not have or have difficulty finding cake flour in your area, you can use the substitute shown below.
Whole Milk. If you do not have buttermilk on hand, you can use whole milk. For a closer thickness to buttermilk, however, you can also use whole milk with 2 teaspoons of lemon juice. Add the lemon juice into the ⅓ measuring cup first, then fill the remaining cup with the whole milk. Pour it into a small glass bowl and let it sit for about 5 minutes to thicken.
I did not test this recipe using any alternative flours, egg substitutes, dairy free alternatives, or cake pans.
Homemade Cake Flour Substitute
If you don't keep cake flour on hand, fear not—you can make it at home! You only need all-purpose flour, cornstarch, and a sifter!
To make homemade cake flour:
- Add 1 tablespoon of cornstarch to a ½ cup measuring cup.
- Fill the remaining measuring cup with all-purpose flour.
- Run the mixture through a sifter. Once is good, but twice is even better!
If you want to have a little more on hand, I recommend doubling the above recipe. Keep it stored in an airtight container either at room temperature or, my preference, the freezer.
What is Flour Buttercream?
Flour buttercream, also known as Ermine buttercream or boiled milk frosting, is frosting made without powdered sugar.
Its ingredients include all-purpose flour, granulated sugar, salt, milk, vanilla extract, and unsalted butter.
While the process is slightly more time consuming, the result gives you a less sweetened buttercream that is similar to swiss meringue, with the creaminess of the classic American buttercream frosting.
How to Make Small Batch Vanilla Flour Buttercream
This buttercream is made in two parts and will take some time.
If you prefer to make my small batch vanilla buttercream with powdered sugar, visit my Small Batch Vanilla Cupcakes recipe.
Step one. Mix your all-purpose flour, granulated sugar, and salt together with a whisk. Add in the milk and whisk once more.
Step two. Over low-medium heat bring the mixture to a near boil, continually stirring with a spatula. It's also a good idea to scrape the bottom of the saucepan too. Your mixture will begin to thicken to the consistency of paste and will have a wet, glossy look to it.
Step three. Turn off the heat and continue to stir and scrape for 1-2 minutes more. This will help release some of the heat as well as remove some of the shine.
Step four. Pour the mixture evenly onto a plate (preferably one with a lip or an edge) and immediately cover with plastic wrap, pressing it directly onto the mixture. This will keep the mixture from forming a skin. Let it cool to room temperature before continuing to the next step.
Tip: To speed up the process you can let it cool down in the refrigerator, then bring it out to let it come to room temperature. Both the thicken mixture and the butter need to be at room temperature.
Step five. Before starting, make sure the butter is at room temperature and cut into cubes. Beat the butter using a stand mixer or a hand mixer for 2-3 minutes or until it's light in color and fluffy in texture.
Step six. Add it one spoonful at a time and not all at once. Let each spoonful mix into the frosting before adding the next spoonful. Once it's all been added, scrape down the sides of the bowl, add in the vanilla extract, and mix once more on medium-high speed.
You can make either the thickened flour mixture or the flour buttercream 3-5 days in advance. Keep it stored in the refrigerator, then bring to room temperature when ready to use.
For the vanilla flour buttercream, you should whisk it again with the mixer to bring it back to life.
Make Your Own Sprinkle Mix
If you want to mix things up a bit with the sprinkles you add to your 6 inch funfetti cake, here's a combination to try! Of course, the sky is the limit for the type of sprinkles you use as well as how many different combinations. For this mix, I used the following 3:
Note the kind that I used have a natural coloring to them and are not super bold and bright. They're more muted in color.
Add a small amount to a jar with a lid (a ball canning jar will work well), make sure the lid is on good and tight, then shake it up. Wah-la—your own sprinkle mix!
Single Layer Cake Troubleshooting / FAQs
Because this is a thicker cake, my recommendation is to use the 6" x 3". If using a 6" x 2", note that the cake will more than likely come right up to the top of the cake pan.
I always recommend using a serrated knife.
This small batch recipe makes approximately 1 ¼ cup of frosting which is enough to cover the entire cake. You can even slice the cake into 2 layers and have enough for a thin layer in between.
It's more than likely you did not let your flour mixture cool 100% completely before mixing it with the butter. Likewise, if your butter is too soft the same thing can occur.
It's possible your flour mixture was not brought to room temperature after cooling. If it's still cool then mixed with your butter (which is also cold), your frosting cane turn out grainy. Both the butter and the flour mixture need to be at room temperature.
I used a combination of rainbow sprinkles, rainbow nonpareils, and rainbow confetti sprinkles. They'll be linked below in the baking tools section!
Essential Funfetti Cake Making Tools
More Single Layer Cakes!
Keep your love of the single layer cake going with any of these fabulous recipes!
Single Layer Funfetti Cake
Author:Ingredients
single layer funfetti cake
- 1 cup Cake Flour
- 1 tsp Baking Powder
- ¼ tsp Salt
- 5 tbsp Unsalted Butter, room temperature
- ½ cup Granulated Sugar
- 1 Large Egg, room temperature
- 1 tsp Vanilla Extract
- ⅓ cup Buttermilk
- ¼ cup Rainbow Jimmies, or rainbow sprinkles
small batch vanilla flour buttercream frosting
- 3 tbsp All-Purpose Flour
- ½ cup Granulated Sugar
- ½ cup Milk
- ¼ tsp Salt
- ½ cup Unsalted Butter, room temperature and cut into pieces
- 1 tsp Vanilla Extract
sprinkle mix (for cake decoration)
- ¼ cup Rainbow Jimmies
- ¼ cup Rainbow Nonpareils
- ¼ cup Rainbow Confetti
Instructions
single layer funfetti cake
- Adjust the oven rack to the 2nd level mark (just above center) and preheat your oven to 350ºF. Generously spray a 6 inch round cake pan (6 x 3 is preferred) with a flour based baking spray. Line the bottom with parchment paper and lightly respray the top.
- In a medium-size mixing bowl, sift together the cake flour, baking powder, and salt. Set to the side.
- Usin your hand mixer and a medium-size mixing bowl or your stand mixer fitted with the paddle attachment, beat together the unsalted butter and granulated sugar on medium high speed until light in color and fluffy in texture.
- Add in the egg and vanilla extract.
- Switch the mixer speed to low, gradually adding the whisked dry mixture alternatively with the buttermilk. Mix until just combined. Fold in your rainbow jimmies (sprinkles).
- Transfer your cake batter to the prepared pan, then bake for 35-40 minutes at 350ºF or until an inserted toothpick comes out clean. Note: a few crumbs on the toothpick is okay, but it should not be cake batter.
- Cool for about 10 minutes in the pan, then carefully invert it onto a wire cooling rack to finish cooling completely. The cake should be completely cooled before frosting as well.
small batch vanilla flour buttercream frosting
- Combine the all-purpose flour, granulated sugar, and salt in a small saucepan. Whisk together, then add in the milk and whisk once more until well combined.
- Over low-medium heat bring the mixture to a near boil, continually stirring with a spatula. It's a good idea to run your spatula along the bottom of the saucepan as well as you stir. Your mixture will begin to thicken to the consistency of paste and will have a wet, glossy look to it. Do not leave this mixture left unattended at any point during this process.
- Once the mixture begins to bubble, turn off the heat and continue to stir and scrape for 1-2 minutes more. This will help release some of the heat as well as remove some of the glossiness.
- Evenly spread out the mixture onto a plate (preferably one with a lip or an edge) and immediately cover with plastic wrap, pressing it directly onto the top of the mixture. This will prevent a skin from forming over the top as it cools. The flour mixture must cool to room temperature before moving on to the next step. See notes below to help speed up the process slightly.
- Before starting, make sure the unsalted butter is at room temperature and cut into cubes. Beat the butter on medium-high speed using a stand mixer or a hand mixer for 2-3 minutes or until it's light in color and fluffy in texture.
- Switching the mixer speed to low, add the room temp flour mixture to the butter one spoonful at a time (not all at once). Let each spoonful mix into the frosting before adding more.
- Once it's all been added, scrape down the sides of the bowl, add in the vanilla extract, and mix once more on medium speed until fully combined. If your frosting does end up having air bubbles, you can use a spatula to press the frosting along the sides of the bowl to remove them.
- You can make either the thickened flour mixture or the flour buttercream 3-5 days in advance. Keep it stored in the refrigerator, then bring to room temperature when ready to use. For the vanilla flour buttercream, you should mix it again for 2-3 minutes with your hand mixer or stand mixer to bring it back to it's fluffy life.
assembling the funfetti cake
- If desired, slice your cooled funfetti cake into 2 layers. Place the first layer onto a half sheet of parchment paper, a serving plate, or cake circle.
- Add a thin layer of the frosting with an offset spatula to the top, then top with the remaining layer. If you'd like before adding the second layer, you can add a few sprinkles to the frosting.
- Once the cake is frosted, add on your sprinkles or sprinkle mix, then enjoy!
Recipe Notes
If you make this single-layer funfetti cake recipe, I would love to hear your feedback! Leaving a comment and rating below is helpful and appreciated not only to me but to other bakers. Thanks!
Tyy says
Hi there. I would love to try this recipe as practice but I don't have a 6" inch pan can this be baked in a 8" pan and still be done as a layered cake ?
Jennifer says
I have not tested this in an 8-inch cake pan, but I imagine you could. It would be a much thinner layer, so I don't think you could turn this into a layered cake unless you doubled the recipe.