It’s my birthday week! And naturally, I decided to use it as an excuse to make my own birthday cake. Don’t worry, there are plenty of other desserts in store for this week (including my favorite Pip’s Doughnuts), plus a trip to the roller skating rink because it sounds like the most fun way to celebrate my birthday ever. For my birthday cake though, I made my Funfetti Cake recipe and topped it with this sprinkle-filled Funfetti Buttercream to make it extra festive! My heart is so happy.


This Funfetti Buttercream uses my favorite Vanilla Buttercream recipe as a base and the added sprinkles make it so cute and fun! I will be honest, it can be a challenge to frost a smooth buttercream cake with it since the sprinkles will drag as you smooth. Luckily though, I’ve got a few tips to make it much less frustrating and help you get that perfectly smooth (and sprinkley!) buttercream finish. Be sure to look at the tutorial below the recipe for everything you need to know.


To top this sprinkle saturated cake, I went with a fuchsia colored shell border which I piped using Wilton Tip 4B. I’m starting to really love a shell border moment (here’s a post that will show you how to do it if you’re into it too). I also topped it with the cutest candles ever from Meri Meri because I just could not help myself.
Here’s a quick video I whipped up to show you how to make this Funfetti Buttercream and frost a cake with it:
PS: If you’re into cake decorating videos like this one, be sure to check out my YouTube Channel! Click the Subscribe button while you’re there so you never miss a new video.
What Type of Sprinkles are Best for Funfetti
There are few things more stressful than realizing your rainbow sprinkles are bleeding into your cake batter and buttercream. This is why it’s so important to choose the right sprinkles for the job. The best kind of rainbow sprinkles to use will be rod-shaped ones that don’t bleed color. Look for confectioner’s glaze in the ingredients list – this seems to be the secret ingredient that coats the rainbow sprinkles enough to where they shouldn’t bleed color.

The sprinkles I love to use for funfetti are the Ultimate Rainbow Jimmies by Sprinkle Pop. They never bleed their color, even when suspended in cake batter, plus I love the cool-toned rainbow hues in the mix. I always stock up so that I can have these on hand for baking and cake decorating.

Funfetti Buttercream
Ingredients
- 1 Cup (226g) unsalted butter, room temperature
- 3 1/2 Cups (420g) powdered sugar
- 2 tsp pure vanilla extract
- 2 Tbsp whole milk, room temperature
- 1/4 tsp salt, or to taste
- 1/4 Cup (50g) rainbow sprinkles* see note
Instructions
- With a hand mixer or stand mixer fitted with the paddle attachment, cream the butter on high until creamy and light (almost white) in color, about 7 minutes.
- Turn the mixer to low speed and add the powdered sugar one cup at a time, scraping down the bowl and paddle after each addition and making sure each cup is fully incorporated before adding the next one.
- Add the vanilla, milk, and salt and mix on low for another minute until fully incorporated and smooth. Fold in the rainbow sprinkles with a rubber spatula.
Notes
- Frost 12-15 cupcakes with a piping bag
- Fill and crumb coat a three-layer 6-inch cake or two-layer 8-inch cake. To have enough for frosting and decorating as well, double the recipe.
Tips for Frosting a Smooth Finish with Funfetti Buttercream
With sprinkles suspended in this buttercream, it can be challenging (but certainly not impossible!) to get a super smooth finish. This is because the sprinkles tend to drag along with your smoother and create trenches in the buttercream. Even so, hopefully these tips help you easily frost your cake, sprinkles and all, into a smooth finish.
Tip 1: Keep the icing smoother at a tight angle. The tighter you can hold the icing smoother, the easier it will be for the smoother to glide over the sprinkles instead of dragging them through the buttercream. It helps to hold the smoother at about a 5 to 10 degree angle. Even still, some sprinkles will definitely drag and create trenches, but not nearly as many as if you were to hold the smoother at a wider angle.
Tip 2: Fill In Trenches. When you do notice some trenches in your buttercream from the sprinkles dragging, don’t stress too much. Simply fill them in with more buttercream and keep smoothing at a tight angle instead of trying to smooth over them without adding any extra buttercream.
Tip 3: Add a Patchwork Layer. If you’re having a really hard time with those trenches, this tip should solve everything. Pop the frosted cake, imperfections and all, into the refrigerator to let the buttercream firm up for 20-30 minutes. Once it’s cold, you can fill in those trenches with buttercream and easily smooth them. You won’t even be able to see where the imperfections once were!

Did you make this Funfetti Buttercream? I want to know how it went! Leave a comment below and feel free to tag @sugarandsparrowco on Instagram to show me your creation. I love to see what you do with my recipes and tutorials!
Another game-changing recipe from Sugar & Sparrow.
I was honestly skeptical at first—I’ve always struggled to make a funfetti cake that didn’t either taste synthetic or bleed into bad tye-dye. That “confectioner glaze” tip was the ticket.
Already getting requests to make this recipe again.
Thank you and very happy birthday!
Yay, Edith! I’m so happy you loved this recipe and that the tip about the sprinkles was a game changer! Thank you for the birthday wishes 🙂