These funfetti birthday cupcakes are the perfect addition to any party table! A moist, light and fluffy sponge cake crowned with a luxuriously smooth Swiss meringue buttercream.

The cupcakes come together easily and the Swiss meringue buttercream is so much easier and beginner-friendly compared to it’s Italian counterpart. Its seriously enough to trick anyone into thinking that these were bought from a gourmet bakery!

key ingredients for the funfetti birthday cupcakes

Cake flour. Has less gluten than all-purpose flour lending to a lighter cake with a more tender crumb
Granulated sugar. Not too overpowering to the delicate vanilla flavor.
Sprinkle jimmies. A fun addition of color plus jimmies don’t bleed easily and dissolve perfectly so there are no texture issues.
Eggs. Separated in this recipe. The yolks provide flavor and make the cake moist and the egg whites are whipped for a fluffy, light texture.
Canola oil. The key to a moist cake since this fat is liquid at room temperature.
Vanilla yogurt. Adds more fat and moisture to the crumb without making the batter too loose and packs in more vanilla flavor!
Baking powder & soda. Work in different ways before baking and during to ensure these cupcakes have the perfect dome.
Vanilla extract. The perfect pairing for this funfetti cake
Lemon juice. Used in whipping the egg whites to help stabilize them to hold their shape.

key ingredients for the swiss meringue buttercream

Meringue powder (or egg whites). Contribute volume when whipped and makes the buttercream more stable
Granulated sugar. The key to making any frosting and along with egg white, ensures a strong, buttercream that holds it’s shape well.
Unsalted butter. Adds a luxurious richness to the buttercream.
Confectioner’s sugar. Add a little more sweetness without making the meringue gritty from too much granulated sugar

tips for the best funfetti birthday cupcakes

Use a kitchen scale for consistent results. Vanilla cakes, especially sponge cakes like this one will be sensitive to any tweaks in ingredient amounts – especially flour which adds more gluten giving a firmer cake.
Soft peaks vs firm peaks. Soft peaks are needed for the whipped egg whites in the cake while firm peaks are needed for the Swiss meringue buttercream.
With soft peaks, when the whisk is inverted the peak with flop over, almost like a Santa’s hat, and eventually will recede back down the whisk.
With firm peaks, when the whisk is inverted the peak will firmly hold its shape and any ridges will be sharp and clear. The peak will flop over but it should hold that shape indefinitely without receding.
Use an oven thermometer! Ovens can have hotspots and/or run lower or higher than the presented reading so an oven thermometer takes out the guess work. I use this one and make sure it reads at needed temperature before starting my baking project.
Don’t open the oven in the middle baking! This allows heat to escape – dropping the temperature of the oven suddenly which affects the rise of the cupcakes and can cause them to sink.
Use unsalted butter in both your cake and buttercream. Sometimes swapping in salted butter only makes a small difference but this recipe is not as forgiving. Since this cake doesn’t need a lot of salt, using salted butter makes it salty without even adding any additional salt so opt for unsalted butter to control the salt flavor.
Meringue powder vs egg whites. Both options are perfectly viable however with meringue powder there is no pressure to use the egg yolks before they go bad.
If you have left over yolks that’s the perfect excuse to make homemade ice cream!
When whipping egg white, ensure that the bowl is clean and grease-free as any oils will prevent it from whipping to maximum volume.

swiss vs italian meringue buttercream

Swiss meringue doesn’t need a sugar syrup so it’s a better option for beginners or if you have a hand mixer. It negates the risk of hard chunks of sugar in the buttercream as well.
Swiss meringue buttercream is less time consuming since you rarely have to wait for the meringue mixture to cool. Since the egg white mixture doesn’t get scaldingly hot once it is whipped to stiff peaks it is typically cool enough to add the butter right away without waiting.
Swiss meringue easier is also much more easier to save at any stage since its easy to troubleshoot any issues before it is too late. For example, if the egg white/sugar mixture is still grainy you can return it to the double boiler to dissolve the sugar. Also, the addition of sugar at that stage makes the egg whites more stable and more difficult virtually impossible to over whip in comparison to Italian meringue buttercream.

how to make the perfect funfetti birthday cupcakes

Step 1. Preheat the oven to 375°F. For 2 8-inch layers double this recipe and bake at 325°F.

Step 2. Start making the cake by mixing the cake flour, baking powder, baking soda, salt and 35 grams of the sugar together in a bowl until evenly combined.

Step 3. Separate your eggs (placing the egg whites in a clean bowl) then add the egg yolks, oil, vanilla and vanilla yogurt to the bowl from step 1 and mix until evenly combined. It’s better to do this by hand since many vanilla cakes (like this one) can be easily over-mixed causing a firmer texture and drier crumb. If you opt to use an electronic mixer do so at the lowest speed and mix until just combined.

Step 4. To your clean bowl containing the egg whites, add the lemon juice and whip until frothy. They should have approximately doubled in volume at this point.

Step 5. Once your egg whites are frothy gradually add the rest of the sugar over about 30 t0 45 seconds. If you add the sugar too fast or early it will result in less volume affecting the cupcakes’ rise.

folding in the whipped egg whites into the batter

Step 6. Once all the sugar is added continue to whip the egg-whites until soft peaks form. Do NOT whip to stiff peaks as this will give the cupcake a drier more “cottony” mouthfeel.

Step 7. Add the sprinkles to the cake batter from step 2 then add the whipped egg whites from the previous step. Gently fold in both until evenly combined (thin ribbons of egg white are ok).
Order matters here as you want to avoid dumping the sprinkles on the egg whites which could cause them to deflate.
Also, ensure you are folding with the lightly to preserve the air incorporated into the egg white – this translates into a light cupcake. For my motion I imagine I am moving in slow motion, scraping down the sides/bottom of my bowl and bringing that batter to the top. Repeat this until the batter looks uniform.

Step 8. Scoop the batter into lined cupcake tins, filling each tin 3⁄4 of the way.

Step 9. Bake for 12-16 minutes or until cupcakes have a golden color and a toothpick comes back with a couple crumbs when inserted. Allow to cool completely before decorating

making the swiss meringue buttercream

Step 10. While the cupcakes cool, start making the Swiss meringue buttercream. Add the meringue powder and water (or egg whites) along with the salt and granulated sugar to a large bowl and, over a double boiler, whisk until sugar has dissolved completely. The mixture will be thick and opaque at this point – very similar to glue.
To test this, touch the mixture to your fingertips – it should be sticky but smooth. If you feel any graininess, return to the double boiler until smooth. This takes about 3-6 minutes.

Step 11. Once meringue powder mixture is smooth, whip into a meringue for 5-7 minutes or until firm, glossy peaks form. The meringue should be at room temperature by this time.
A stand mixer makes this step easier but a hand mixer will also get the job done. If using a handheld mixer, move the mixer around in a circular motion or rotate the bowl while whipping – this ensures that the meringue is whipped evenly.

Step 12. Cut your softened butter into chunks (approximately half to 1-inch cubes) and add one at time waiting until the previous is completely incorporated before adding another. It’s normal for the meringue to deflate a bit after the first couple additions of butter and even look a little runny but trust the process!

Step 13. Once all the butter has been added to the buttercream, add the confectioner’s sugar & lemon juice and whip again until smooth.

Step 14. Using a piping bag with your piping tip of choice, or simply just a spatula, pipe or spread the buttercream onto your cooled funfetti birthday cupcakes and enjoy! For best flavor store in an airtight container and enjoy within 2 days.