Rich Chocolate Peanut Butter Cake with Peanut Butter Frosting

This chocolate peanut butter cake is the one I bake when a plain chocolate cake feels like it is missing something.

The layers are dark and tender from buttermilk and oil, and the frosting is a salted peanut butter buttercream that hits that salty-sweet note you want. No cake mix required, and it comes together in about an hour.

Why This Cake Stays in the Rotation

I make this cake for birthdays, potlucks, and any Tuesday that calls for chocolate. The oil keeps the crumb soft for days, and the peanut butter frosting is just sweet enough with a salty edge that cuts through the richness.

When you slice into it, you get a deep chocolate flavor that actually holds up next to the peanut butter. It is the kind of cake that makes people ask for the recipe, and I am happy to share it because it never fails.

Ingredients

• 2 cups all-purpose flour: spooned and leveled
• 2 cups granulated sugar
• 3/4 cup unsweetened cocoa powder: Dutch-processed gives the deepest flavor
• 2 teaspoons baking powder
• 1 teaspoon baking soda
• 1 teaspoon fine sea salt
• 2 large eggs, room temperature
• 1 cup buttermilk, room temperature
• 1/2 cup vegetable oil
• 2 teaspoons vanilla extract
• 1 cup hot brewed coffee: or hot water

Peanut Butter Frosting

• 1 cup unsalted butter, softened
• 1 cup creamy peanut butter: use a shelf-stable kind, not natural
• 3 to 4 cups powdered sugar
• 1/4 cup heavy cream or whole milk
• 1 teaspoon vanilla extract
• 1/2 teaspoon fine sea salt: plus more to taste
• 1/2 cup chopped roasted peanuts: for garnish

Variations / Substitutions

• No buttermilk: Stir 1 tablespoon white vinegar or lemon juice into 1 cup whole milk and let it sit for 5 minutes before using.
• No coffee: Replace the hot coffee with hot water; the cake will still be tender but slightly less complex.
• Gluten-free: Swap the flour for a 1:1 gluten-free baking blend that contains xanthan gum.
• Crunchy bits: Fold 1 cup of mini chocolate chips into the batter before baking for extra texture.
• Peanut butter base: Do not use natural peanut butter in the frosting; it separates and turns greasy. Stick with the no-stir creamy kind like Jif or Skippy.

If you love this pairing, you should make my peanut butter chocolate chip cookies next.

How to Make Chocolate Peanut Butter Cake

Step 1: Mix the Dry Ingredients

Preheat the oven to 350°F (175°C). Butter and flour two 9-inch round cake pans, then line the bottoms with parchment. In a large bowl, whisk together the 2 cups flour, 2 cups sugar, 3/4 cup cocoa powder, 2 teaspoons baking powder, 1 teaspoon baking soda, and 1 teaspoon salt.

Take a moment to whisk thoroughly so the cocoa and leaveners are evenly distributed. Any lumps of cocoa will show up as dry pockets later.

Step 2: Whisk the Wet Ingredients

In a separate large bowl, whisk the 2 eggs, 1 cup buttermilk, 1/2 cup oil, and 2 teaspoons vanilla until smooth. The mixture will be pale and slightly thickened.

Room-temperature ingredients help the batter blend seamlessly, so pull the eggs and buttermilk out of the fridge about 30 minutes before you start.

Step 3: Blend the Batter

Pour the wet ingredients into the dry ingredients and stir with a spatula until just combined. Then slowly pour in the 1 cup of hot coffee while stirring. The batter will be thin, which is exactly what you want.

Stop mixing as soon as no streaks of flour remain. Overworking the batter right now can make the cake tough, so a few small lumps are fine.

Step 4: Bake the Layers

Divide the batter evenly between the prepared pans. Tap each pan gently on the counter to release any large air bubbles. Bake for 30 to 35 minutes, rotating the pans halfway through, until a toothpick inserted in the center comes out with a few moist crumbs.

The tops will spring back when lightly pressed. Let the cakes cool in the pans for 10 minutes, then run a knife around the edges and turn them out onto a wire rack to cool completely.

Step 5: Frost and Stack the Cake

While the cakes cool, make the frosting. Beat 1 cup softened butter and 1 cup peanut butter with an electric mixer until creamy. Gradually add 3 cups of powdered sugar, alternating with the 1/4 cup cream, and beat until light and fluffy. Mix in 1 teaspoon vanilla and the 1/2 teaspoon salt, then taste and add a pinch more salt if you like it saltier.

Place one completely cooled cake layer on a plate or stand. Spread about 1 cup of frosting over the top. Set the second layer on top, then frost the top and sides with the remaining frosting. Use the back of a spoon to make swirls, and press the 1/2 cup chopped peanuts around the sides or sprinkle them on top. Slice and serve at room temperature for the best texture.

A Few Tips for a Great Chocolate Peanut Butter Cake

• Use room-temperature buttermilk and eggs. Cold ingredients can cause the batter to seize and the crumb to be dense.
• Measure the flour by spooning it into the cup and leveling it off. Too much flour is the fastest way to a dry cake.
• Let the cake layers cool completely before frosting. Even a little warmth will melt the buttercream and turn it into a drippy mess.
• For the cleanest slices, chill the assembled cake in the fridge for 20 minutes, then cut with a sharp, thin knife wiped clean between cuts.

Bake times by pan size (all at 350°F / 175°C):

Storing Leftover Cake

• Refrigerate: Cover the cake tightly and store in the fridge for up to 5 days. Let slices come to room temperature before serving.
• Freeze unfrosted layers: Wrap the completely cooled layers in plastic wrap, then foil, and freeze for up to 2 months. Thaw at room temperature, then frost and assemble as usual.

Frequently Asked Questions

Can I use natural peanut butter in the frosting?

No. Natural peanut butter is too thin and oily, and the frosting will separate. You need the shelf-stable creamy kind.

Can I make this cake gluten-free?

Yes. Swap the all-purpose flour for a 1:1 gluten-free baking flour blend that contains xanthan gum. The texture will be slightly more delicate but still excellent.

Why did my frosting turn out grainy?

It is likely the powdered sugar was not fully incorporated, or the butter was too cold. Make sure the butter is truly soft, and beat the frosting for at least 3 minutes after adding the sugar to dissolve it completely.

Can I use a different frosting?

Of course. A chocolate ganache or cream cheese frosting works well here too, but the peanut butter cream is what makes it the cake everyone remembers.

Chocolate Peanut Butter Cake Recipe

Print Recipe Pin Recipe

Prep Time 30 minutes mins

Cook Time 35 minutes mins

Total Time 1 hour hr 5 minutes mins

Servings: 12 servings

Calories: 580

Ingredients Method Notes

Ingredients

  

• 2 cups all-purpose flour
• 2 cups granulated sugar
• 3/4 cup unsweetened cocoa powder
• 2 teaspoons baking powder
• 1 teaspoon baking soda
• 1 teaspoon fine sea salt
• 2 large eggs, room temperature
• 1 cup buttermilk, room temperature
• 1/2 cup vegetable oil
• 2 teaspoons vanilla extract
• 1 cup hot brewed coffee
• 1 cup unsalted butter, softened
• 1 cup creamy peanut butter
• 3 to 4 cups powdered sugar
• 1/4 cup heavy cream or whole milk
• 1 teaspoon vanilla extract
• 1/2 teaspoon fine sea salt
• 1/2 cup chopped roasted peanuts

Method

 

1. Preheat the oven to 350°F (175°C). Butter and flour two 9-inch round pans and line with parchment. Whisk flour, sugar, cocoa, baking powder, baking soda, and salt in a large bowl.
2. In another bowl, whisk eggs, buttermilk, oil, and vanilla until smooth.
3. Pour wet into dry, stir until just combined, then slowly stir in hot coffee. The batter will be thin.
4. Divide between pans, tap out air bubbles, and bake for 30 to 35 minutes until a toothpick comes out with a few moist crumbs. Cool in pans 10 minutes, then transfer to a rack to cool completely.
5. For the frosting, beat butter and peanut butter until creamy. Alternate adding powdered sugar and cream, beat until fluffy, then mix in vanilla and salt. Spread frosting over one layer, stack the second, frost the top and sides, and garnish with chopped peanuts.

Notes

For an extra chocolate boost, replace 1/4 cup of the buttermilk with strong brewed coffee in the batter. The cake tastes best at room temperature, so let it sit out for 20 minutes after chilling.