Save This vibrant frosting blends softened butter, sifted powdered sugar, vanilla, and crushed Fruity Pebbles for a fluffy, colorful topping. Pulse most of the cereal to integrate flavor, reserving whole pieces as a garnish. Adjust milk to reach a spreadable or pipeable consistency. Works beautifully on cupcakes, cakes, and cookies; swap plant-based butter and milk for a dairy-free option.
My niece turned seven last spring and requested a rainbow party with zero hesitation, which sent me down a rabbit hole of colorful everything, including this frosting that tastes like Saturday morning cartoons in spreadable form.
I brought a batch to that rainbow party and watched a table full of second graders go completely silent mid bite, which is the only honest review that matters.
Ingredients
- Unsalted butter (1/2 cup, softened): Pull it out an hour ahead so it creams smoothly without lumping.
- Powdered sugar (2 cups, sifted): Sifting is not optional here because nobody wants a gritty frosted cupcake.
- Milk (2 to 3 tbsp): Whole milk gives the richest texture but any milk works fine.
- Vanilla extract (1 tsp): It rounds out the sweetness and keeps the flavor from tasting one dimensional.
- Fruity Pebbles cereal (1 cup, divided): The magic ingredient that turns basic buttercream into something kids and adults fight over.
Instructions
- Crush the cereal:
- Pulse three quarters of a cup of Fruity Pebbles in a food processor or blender until they resemble fine crumbs, then set the remaining quarter cup aside for finishing.
- Beat the butter:
- Beat the softened butter in a large mixing bowl with a hand mixer or stand mixer until it turns pale, creamy, and completely smooth with no cold chunks hiding in the center.
- Add the sugar gradually:
- Pour in the powdered sugar on low speed a little at a time so it does not puff up and coat your entire kitchen in a white cloud.
- Bring in the flavor:
- Add the crushed cereal, vanilla extract, and two tablespoons of milk, then beat until everything is fluffy and uniformly blended, adding a third tablespoon of milk if it feels too stiff.
- Frost your treats:
- Spread or pipe the frosting onto fully cooled cupcakes, cookies, or cake layers so the butter does not melt on contact.
- Finish with crunch:
- Sprinkle the reserved whole Fruity Pebbles over the top right before serving so they stay bright and crispy.
Save That rainbow party frosting disappeared so fast I ended up making a second batch the next morning just so I could actually taste it myself.
Tools That Make This Easy
A food processor is the quickest path to evenly crushed cereal, but a zip top bag and a rolling pin work if you do not mind a bit of an arm workout.
Making It Your Own
Swap in plant based butter and oat milk for a dairy free version that still tastes like childhood, or add a drop of pink food coloring for extra vibrancy.
Pairing and Storage
This frosting loves vanilla and strawberry cake layers best, and it holds up in the fridge for three days if you keep it covered tight so it does not absorb fridge smells.
- Let chilled frosting come to room temperature and give it a quick rewhip before using.
- Freeze leftover frosting in an airtight container for up to one month.
- Always garnish with whole cereal pieces at the very last second for maximum crunch.
Save Keep this one in your back pocket for any celebration that calls for a little joy, and trust me, that is most of them.
Recipe FAQs
- → How should I crush the Fruity Pebbles if I don't have a food processor?
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Place the cereal in a sturdy zip-top bag, seal, and crush with a rolling pin or the bottom of a heavy pan until mostly fine. Work in short bursts to avoid turning everything to dust.
- → Will the crushed cereal make the frosting gritty over time?
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Crushed cereal adds texture at first but can soften as it absorbs moisture. Use the frosting soon after making for the best crunch, and reserve whole pieces for garnish to keep a bright, crisp finish.
- → Can I make a dairy-free version?
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Yes. Substitute plant-based butter and a neutral non-dairy milk. You may need slightly less or more liquid depending on the fat content, so add milk gradually until the desired consistency is reached.
- → Is this frosting suitable for piping?
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Yes—beat to a stiff, pipeable texture by reducing milk to one tablespoon and chilling briefly if needed. For looser spreadable frosting, add the extra tablespoon of milk and beat until smooth.
- → What flavor pairings work best with this topping?
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This colorful topping complements vanilla, strawberry, and funfetti bases especially well. It also balances simple butter or sponge cakes with a playful crunchy finish.
- → Are there allergen considerations I should note?
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Yes. The cereal and base contain milk, gluten (the cereal may include wheat), and soy. Always check packaging for potential traces of nuts or other allergens before serving.
