This white chocolate cake with white chocolate buttercream is a two layer 8 inch cake made with 10 ounces of real white chocolate: 6 ounces melted into the batter and 4 ounces whipped into the frosting. It takes about 1 hour 45 minutes from start to finish (25 minutes prep, 30 to 35 minutes in the oven, then cooling), serves 12, and the sour cream keeps the crumb soft for days.
You know that bland white cake you have probably had at a wedding? This is not that. Because the chocolate goes into both the cake and the buttercream, you taste creamy cocoa butter richness from the first bite, not just sweetness.
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- Yield: 12 slices from one 2 layer 8 inch round cake
- Time: 25 minutes prep, 30 to 35 minutes baking at 350°F (175°C), about 45 minutes cooling, 1 hour 45 minutes total
- White chocolate: 6 oz (170g) in the cake, 4 oz (113g) in the buttercream
- Crumb: 2½ cups flour, 4 whole eggs, 1 cup whole milk, and ½ cup sour cream for a soft, moist layer
- Buttercream: 1 cup butter, 3 cups powdered sugar, 2 to 3 tablespoons heavy cream or milk
- Storage: up to 4 days covered in the fridge, slices freeze for up to 2 months
Why Real White Chocolate Goes in Both Layers and Frosting
Most white cakes get their flavor from vanilla alone. Here, melted white chocolate is beaten into the creamed butter, sugar, and eggs, so the cocoa butter coats the flour and gives the layers a silky, slightly dense richness. The same chocolate in the buttercream ties the whole cake together.
Use bars, not chips. White chocolate chips are made to hold their shape in cookies, so they melt thick and can turn grainy. Go for bars with at least 28% cocoa butter. I usually buy Lindt or Ghirardelli. Chop the bar finely and melt it in short bursts in the microwave or over a pan of barely simmering water, stirring often, then let it cool until it feels just warm before it goes into the batter.
White Chocolate Cake vs White Cake: What Is the Difference?
A classic white cake is usually made with egg whites only and gets its flavor from vanilla, which is why it looks snowy and tastes light. This white chocolate cake uses 4 whole eggs plus melted white chocolate and sour cream, so the crumb is a soft ivory color, a little richer, and more moist. If you want a plain everyday layer, my simple moist vanilla cake is the lighter choice. When you want a cake that actually tastes like white chocolate, this is the one.
The frosting follows the same idea. A standard American buttercream is butter and sugar. White chocolate buttercream adds melted chocolate, which makes it creamier, less sharp in sweetness, and a little firmer once chilled. For a whipped, less sweet finish you could also use Swiss meringue buttercream.
How Do You Keep the Layers Tender?
Start with room temperature butter, eggs, milk, and sour cream. Cold dairy will curdle the batter, so I lay everything out an hour before baking. Beat the butter and granulated sugar on medium high for 3 to 4 minutes, until pale and fluffy. That is where the structure builds.
Add the eggs one at a time, beating well after each, then the vanilla. Pour in the melted white chocolate and mix until the batter turns smooth and creamy. It becomes the kind of batter you could almost eat with a spoon, but let it bake.
Sift the flour, baking powder, baking soda, and salt together. On low speed, add half the dry ingredients, then the milk and sour cream, then the rest of the dry ingredients. Stop as soon as no streaks of flour remain. Overmixing at this stage is what makes a white chocolate cake tough. I always use full fat sour cream and whole milk here; lighter swaps just do not hold the same texture or taste.
Divide the batter evenly between two greased and parchment lined 8 inch round pans, smooth the tops, and bake at 350°F (175°C) for 30 to 35 minutes, until a toothpick in the center comes out clean.
Cooling and Leveling the Layers
Let the layers rest in the pans for 10 minutes, then turn them out onto a wire rack and cool them completely before frosting.
If the centers settle a little as they cool, like the layers in this photo, trim the raised edges with a serrated knife or simply fill the dip with an extra swipe of buttercream. A deep dip usually means the cake came out a few minutes early, so next time test with a toothpick right in the middle before pulling the pans.
Making White Chocolate Buttercream That Spreads Like Silk
This is not one of those sickly sweet frostings that overpowers the cake. It is soft, creamy, and light on the tongue. Beat 1 cup of room temperature butter for about 2 minutes, until creamy. The butter should press easily with your finger: not melted, not firm.
Add the 4 ounces of melted and cooled white chocolate and beat until fully blended. Add the powdered sugar one cup at a time, then the vanilla and a pinch of salt. Drizzle in the cream or milk one tablespoon at a time until the frosting spreads without tearing the crumb, then beat for 2 more minutes so it turns fluffy.
To assemble, set one layer on a plate, spread a layer of buttercream over the top, add the second layer, and frost the top and sides. Want a thicker filling between the layers? A spoonful of white chocolate ganache filling or a thin layer of raspberry cake filling both work well. If you only need the frosting for cupcakes, my separate white chocolate frosting recipe is sized for that.
If the Chocolate Seizes or the Batter Curdles
- Chocolate turned thick and lumpy while melting: it seized, often from a drop of water or steam. Double check that your bowl and spatula are completely dry, and melt in short bursts so it never gets hot.
- Batter looks curdled: the eggs, milk, or sour cream were cold. Keep mixing on low; once the dry ingredients go in it usually smooths out.
- Buttercream is runny: the chocolate was still warm or the kitchen is hot. Chill the bowl for 15 minutes, then beat again.
- Buttercream is too stiff: add cream or milk one teaspoon at a time.
- Cake tastes too sweet: white chocolate brands vary. Add the powdered sugar gradually and taste as you go, and keep the pinch of salt.
Serving Ideas: Curls, Raspberries, and a Slight Chill
This cake shines with simplicity. Shave a few white chocolate curls over the top with a vegetable peeler, and add a cluster of fresh raspberries if you are feeling bold. For something more dressed up, drizzle a little raspberry coulis over each slice; that tart edge balances the sweetness.
I often serve it slightly chilled. The buttercream holds its shape better, the slices cut cleanly, and each layer holds together without crumbling. That makes it ideal for neat dessert plates at birthdays, or for a fork straight from the fridge.
Keeping Leftovers Fresh
Store the cake covered in the fridge for up to 4 days. Let slices sit at room temperature for a bit before serving so the buttercream softens and the white chocolate flavor comes forward. You can also wrap individual slices well and freeze them for up to 2 months. I have stashed leftovers this way before trips and come home to a very welcome surprise.
Baker Questions About White Chocolate Cake
What goes into a white chocolate cake with white chocolate buttercream?
Butter, sugar, 4 eggs, flour, whole milk, sour cream, and 6 oz melted white chocolate for the layers, and butter, 4 oz melted white chocolate, powdered sugar, vanilla, and a little cream for the buttercream.
How much white chocolate do I need for the whole cake?
10 ounces (283g) in total: 6 ounces for the cake batter and 4 ounces for the buttercream. Buy bars with at least 28% cocoa butter.
Can I use white chocolate chips?
It is better not to. Chips are made to hold their shape, so they melt thick and can make the batter and buttercream grainy. Chopped bars melt smoothly.
Can I put white chocolate buttercream on a chocolate cake?
Yes. This buttercream is lovely on a dark chocolate sheet cake or chocolate layers if you want a chocolate and white chocolate cake. One batch covers a 2 layer 8 inch cake.
Can I make this cake ahead for a birthday?
Yes. Bake the layers a day ahead, wrap them once cool, and frost the next day, or frost the whole cake and keep it covered in the fridge for up to 4 days.
Why does my white chocolate buttercream look grainy?
Usually the chocolate seized or was still warm when it hit the butter. Melt it gently, let it cool until just warm, and use bars instead of chips.
This cake taught me that white chocolate is not boring when treated right. If you love it as much as I do, try white chocolate coconut cake next, a no bake raspberry white chocolate cheesecake, or smaller treats like white chocolate donuts and white chocolate macadamia nut cookies. If you bake this one, leave a comment below. I would love to hear how it turned out.
White Chocolate Cake with White Chocolate Buttercream
This white chocolate cake with white chocolate buttercream is a two layer 8 inch cake made with butter, eggs, sour cream, whole milk, and 10 ounces of real white chocolate. It takes about 1 hour 45 minutes including cooling and serves 12, with a soft, moist, tender crumb and a creamy, silky frosting. Melted white chocolate goes into both the batter and the buttercream, so the cake tastes of white chocolate instead of plain vanilla, and the sour cream keeps it moist for days. Bake it as a birthday cake, fill it with raspberries or white chocolate ganache, or use the white chocolate buttercream on chocolate cake or cupcakes. Keep it covered in the fridge for 4 days or freeze slices for 2 months.
Ingredients
- FOR THE CAKE LAYERS
- 2 ½ cups (312g) all-purpose flour
- 2 tsp baking powder
- ½ tsp baking soda
- ½ tsp salt
- ¾ cup (170g) unsalted butter, room temperature
- 1 ½ cups (300g) granulated sugar
- 4 large eggs, room temperature
- 1 tbsp pure vanilla extract
- 6 oz (170g) high-quality white chocolate, melted and slightly cooled
- 1 cup (240ml) whole milk, room temperature
- ½ cup (120ml) sour cream, room temperature
- FOR THE WHITE CHOCOLATE BUTTERCREAM
- 1 cup (226g) unsalted butter, room temperature
- 4 oz (113g) white chocolate, melted and cooled
- 3 cups (360g) powdered sugar, sifted
- 1 tbsp vanilla extract
- 2–3 tbsp heavy cream or milk (as needed for consistency)
- A pinch of salt
Instructions
- PREHEAT AND PREPARE: Preheat the oven to 350°F (175°C). Grease and line two 8-inch round cake pans with parchment paper and set aside.
- SIFT AND MIX THE DRY INGREDIENTS: In a medium bowl, sift together the flour, baking powder, baking soda, and salt. Stir to combine and set aside.
- CREAM THE BUTTER AND SUGAR: In a large bowl or stand mixer, beat the butter and granulated sugar on medium-high speed for 3–4 minutes until light and fluffy. Scrape down the sides of the bowl as needed to ensure even mixing.
- ADD EGGS AND VANILLA: Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract until fully incorporated.
- INCORPORATE WHITE CHOCOLATE: Pour in the melted white chocolate and mix until the batter is smooth and creamy.
- ALTERNATE WET AND DRY INGREDIENTS: On low speed, add half of the dry ingredients to the batter. Then add the milk and sour cream. Finish with the remaining dry ingredients and mix just until combined. Do not overmix.
- BAKE: Divide the batter evenly between the prepared pans. Smooth the tops and bake for 30–35 minutes, or until a toothpick inserted into the center of the cakes comes out clean.
- COOL: Let the cakes cool in the pans for 10 minutes. Carefully remove the cakes from the pans and transfer to a wire rack to cool completely before frosting.
- MAKE THE BUTTERCREAM: In a large mixing bowl, beat the butter on medium speed for about 2 minutes until creamy. Add the melted white chocolate and beat until fully blended. Gradually add the powdered sugar, one cup at a time, mixing well after each addition.
- FINISH THE BUTTERCREAM: Add the vanilla extract and a pinch of salt. Slowly drizzle in the heavy cream or milk, one tablespoon at a time, beating until the frosting reaches a smooth, spreadable consistency. Beat for an additional 2 minutes to make the buttercream fluffy.
- ASSEMBLE THE CAKE: Once the cake layers are completely cool, place one layer on a serving plate. Spread a layer of buttercream over the top. Add the second cake layer and frost the top and sides of the cake evenly with the remaining buttercream.
Notes
Use white chocolate bars with at least 28% cocoa butter, not chips; chips melt thick and can make the batter or frosting grainy. Melt the chocolate gently in short bursts with a completely dry bowl so it does not seize, and let it cool until just warm before using. Bring butter, eggs, milk, and sour cream to room temperature so the batter does not curdle. If the buttercream is too soft, chill it for 15 minutes and beat again. Store the cake covered in the refrigerator for up to 4 days and let slices sit at room temperature briefly before serving. Wrapped slices freeze for up to 2 months.
Nutrition Information
Yield
12Serving Size
1Amount Per Serving Calories 582Total Fat 33gSaturated Fat 20gTrans Fat 1gUnsaturated Fat 11gCholesterol 120mgSodium 368mgCarbohydrates 60gFiber 1gSugar 39gProtein 10g
