This easy funfetti cake recipe is soft, buttery, and full of rainbow sprinkles, all in one pan. It's my go-to celebration cake, straight from my book Entertaining with Charm!
Preheat the oven to 350°F. Butter a 9x13 pan well (or two 8-inch pans lined with parchment).
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
In a stand mixer, beat the butter and sugar on medium until light and fluffy, about 2 to 3 minutes.
Add the egg whites one at a time, beating after each. Then beat in the whole egg.
In a measuring cup with a spout, combine the milk, oil, vanilla, and almond extract.
With the mixer on low, alternate adding the dry ingredients and the milk mixture, beginning and ending with the dry. Mix just until combined. Don't overmix!
Toss the sprinkles with a teaspoon of flour, then gently fold them into the batter.
Pour into the prepared pan and bake for 25 to 30 minutes, until a toothpick in the center comes out clean or with a few soft crumbs. Ovens vary, so check early.
Cool completely before frosting. I know, the waiting is the hardest part.
Frost the cooled cake with about 2 cups, swooping as you go, and finish with a generous shower of sprinkles.
Notes
Sprinkles: Use rainbow jimmies, the long skinny ones from the baking aisle. Nonpareils (the tiny balls) bleed color into the batter, turning your pretty cake gray. Toss the sprinkles with a teaspoon of flour before folding them in so they stay put instead of sinking.Room-temp everything: Let the butter, egg whites, and milk come to room temperature before you start. Everything blends more beautifully, and the cake bakes up softer.Measure flour like a pro: Spoon it into the cup, then level it with a knife. Scooping packs of extra flour, and that's how dry cake happens.Pan options: This bakes beautifully in a 9x13, two 8-inch pans for a layer cake, or as cupcakes. For cupcakes, fill liners ¾ full and bake about 20 minutes.Frosting: You'll need one batch of my Swiss meringue buttercream, about 2 cups. Make sure the cake is completely cool before frosting or it will slide right off. I know, waiting is the hardest part.How to Store: Store frosted cake in an airtight container at room temp for up to 5 days. Unfrosted cake can be frozen for up to 3 months. Thaw overnight in the fridge, then frost. Skip freezing once it's frosted; the meringue buttercream doesn't hold up well in there.