Keto Vanilla Birthday Cake
Published July 29, 2025
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This keto birthday cake is everything a celebration cake should be—fluffy, moist, and spongy with rich vanilla flavor and creamy vanilla buttercream. No dry, gritty, dense texture here—just the perfect gluten-free, low-carb cake that tastes like the real deal thanks to a few game-changing ingredients.
1 slice
16
Servings
372
Calories
36.6g
Fat
6.5g
Protein
1.7g
Net Carb
33.2g
Total Carbs
Disclaimer: The nutrition information provided is an estimate and is for informational purposes only. I am a Doctor of Pharmacy (Pharm.D.); however, this content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always consult your physician or other qualified health provider before making any lifestyle changes or beginning a new nutrition program.
If you’ve been on the hunt for a keto birthday cake that actually tastes like cake—not cornbread, not a brick, not something you politely choke down in front of your low-carb friends—this is it. This keto white cake has the soft, fluffy crumb and sweet vanilla flavor you’d expect from a classic celebration cake, plus a dreamy vanilla buttercream frosting that you’ll want to eat with a spoon. I’ll be honest, my chocolate keto cake usually steals the show around here, but after serving this at a family birthday party, even my chocolate lovers were converted. It’s light, spongy, and doesn’t scream “I’m on a diet,” which is exactly what a birthday cake should be.
What sets this cake apart from all the other almond flour-based keto cakes out there? The secret’s in the texture—and trust me, that matters more than anything when you’re trying to recreate a traditional cake experience. Most low-carb cakes end up dense, dry, or worse… greasy. I wanted this one to have bounce. Soft, cloud-like bounce. So I brought in two MVP ingredients: oat fiber and whey protein isolate. Oat fiber adds that zero-carb, delicate fluff factor (it’s the insoluble part of oat husks, not actual oats), and whey protein gives the cake structure and lift, making it feel light instead of heavy.
It took a few test rounds and a couple tragic cake fails, but this final version is everything I wanted in a vanilla keto cake. It’s naturally gluten-free, has just the right amount of sweetness, and doesn’t rely on coconut flour or a dozen eggs to get the job done.
Why this keto white cake is worth baking
- Actually fluffy. Like boxed cake mix fluffy. No weird dense texture or dry crumb.
- No coconut flavor or gritty mouthfeel. I skip the coconut flour and lean into almond flour, oat fiber, and protein powder for a smoother bite.
- Zero weird aftertaste. I use sweeteners that don’t overpower the vanilla flavor.
- Perfect for non-keto eaters. No one will know it’s low-carb…unless you tell them.
- Customizable. Use it as a base for cupcakes, layer cakes, or even a wedding cake (yes, really).
So go ahead, stick some candles in it. This one deserves a celebration!
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Keto White Cake Ingredients
2 cups almond flour -
2 tablespoons oat fiber
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1/4 cup unflavored whey protein isolate
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1 tablespoon baking powder
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1/2 teaspoon salt
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6 egg whites, room temperature
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1/2 cup unsalted butter, melted
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1/3 cup plain Greek yogurt or sour cream
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1 cup sugar-free sweetener
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1 tablespoon vanilla extract
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1/4 cup unsweetened nut or seed milk
Double Batch Keto Vanilla Buttercream Frosting Ingredients
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2 cups unsalted butter, softened room temperature
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1 1/2 cups powdered sugar-free sweetener
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1 1/2 tablespoons vanilla extract
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1/4 cup heavy cream
Step by Step Instructions
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Preheat oven & prepare cake pans
Preheat oven to 350°F. Line two 8-inch round cake pans with parchment and lightly grease the sides with butter. Set aside.
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Mix dry ingredients
In a large bowl, whisk together almond flour, oat fiber, whey protein powder, baking powder, and salt. Set aside.
Ingredients
- 2 cups almond flour
- 2 tablespoons oat fiber
- 1/4 cup protein powder
- 1 tablespoon baking powder
- 1/2 teaspoon salt
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Beat egg whites
In another large bowl, whisk the egg whites until slightly frothy, about 2 minutes.
Ingredients
- 6 egg whites, room temperature
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Add remaining wet ingredients
To the egg whites, add melted butter, yogurt, sugar-free sweetener, vanilla, and milk of choice.
Ingredients
- 1/2 cup unsalted butter, melted
- 1/3 cup plain Greek yogurt or sour cream
- 1 cup sugar-free sweetener
- 1 tablespoon vanilla extract
- 1/4 cup milk of choice
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Finish cake batter
While mixing with an electric mixer, pour the ingredients into the dry ingredients and stir until just combined.
Quick Tip
Batter should be thick but spreadable—add a splash more milk if too dry. -
Bake the cake
Divide evenly between pans and smooth the tops. Bake at 350°F for 20–25 minutes, or until tops are set and a toothpick comes out clean. Let cool in pans 10 min, then transfer to wire racks.
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Make the buttercream frosting
In a large, clean bowl, beat the softened butter with an electric mixer until pale and fluffy (about 4-5 minutes). Add sweetener and beat until combined. Mix in vanilla, then gradually add heavy cream until desired consistency is reached. Frost cooled cake layers.
Ingredients
- 2 cups unsalted butter, softened
- 1 1/2 cups powdered sugar-free sweetener
- 1 1/2 tablespoons vanilla extract
- 1/4 cup heavy cream
I can’t believe how moist and tender the cake turned out without using any regular flour. The vanilla flavor was deep and satisfying and the buttercream had the perfect creamy texture. Total winner for any keto celebration!
This cake totally blew my mind with how fluffy it was for being low carb. I especially loved how the combination of Greek yogurt and almond flour made it so rich without feeling heavy. Five stars for making keto feel indulgent!
This cake had such a beautiful golden top and the texture reminded me of a classic sponge from my childhood. The hint of tang from the yogurt added a nice contrast to the sweet frosting. Definitely impressed with how well it held together without any crumbling.