One-Bowl Chocolate Cake
A deeply moist, fudgy chocolate cake that comes together in a single bowl with a whisk—no mixer, no creaming, no fuss. Boiling water and a full cup of cocoa bloom into an intensely dark, tender crumb that stays soft for days.
Whisk all the dry ingredients in one large bowl, add eggs, buttermilk, oil, and vanilla, then stir in a cup of boiling water (or hot coffee) to bloom the cocoa. The batter will be thin—that is correct, and it is the secret to the moist crumb. Divide between two greased and parchment-lined 9-inch pans and bake at 350°F (175°C) for 30 to 35 minutes until a toothpick comes out with a few moist crumbs. Cool completely before frosting.
- The batter is intentionally thin—boiling water blooms the cocoa for maximum flavor and a tender crumb.
- One bowl, one whisk, no mixer required; total hands-on time is about 15 minutes.
- Hot coffee amplifies the chocolate without tasting like coffee—use it in place of the water.
Equipment
- Two 9-inch round cake pans
- Large mixing bowl
- Whisk
- Parchment paper
- Wire cooling rack
- Offset spatula
Ingredients
Cake
- 250 g all-purpose flour, spooned and leveled
- 400 g granulated sugar
- 85 g unsweetened cocoa powder, natural or Dutch-process
- 9 g baking soda
- 5 g baking powder
- 6 g fine salt
- 2 large eggs, room temperature
- 240 ml buttermilk, room temperature
- 120 ml neutral oil, canola or vegetable
- 10 ml pure vanilla extract
- 240 ml boiling water or hot brewed coffee, coffee deepens the chocolate flavor
Chocolate Buttercream
- 227 g unsalted butter, softened
- 360 g powdered sugar, sifted
- 60 g unsweetened cocoa powder, sifted
- 60 ml heavy cream, plus more as needed
- 5 ml pure vanilla extract
- 1 g fine salt
Method
- STEP01
Position a rack in the center of the oven and heat to 350°F (175°C). Grease two 9-inch round cake pans, line the bottoms with parchment rounds, then grease the parchment and dust with cocoa powder. This is a wet, sticky batter—do not skip the parchment.
- STEP02
In one large bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt until uniform and no cocoa streaks remain. Break up any cocoa lumps against the side of the bowl with the whisk.
- STEP03
Add the eggs, buttermilk, oil, and vanilla directly to the dry ingredients. Whisk just until the batter is smooth and no dry pockets remain, about 1 minute. Do not overmix—stop the moment it comes together.
- STEP04
Carefully whisk in the boiling water or hot coffee until fully incorporated. The batter will be very thin, almost like a thick hot chocolate—this is exactly right and is what makes the cake so moist. Scrape the bottom of the bowl to catch any thick spots.
- STEP05
Divide the batter evenly between the two prepared pans (about 600 g each if you weigh them). Bake for 30 to 35 minutes, until the cakes spring back lightly when pressed and a toothpick inserted in the center comes out with a few moist crumbs but no wet batter.
- STEP06
Cool the cakes in their pans on a wire rack for 15 minutes, then run a thin knife around the edges, invert onto the rack, peel off the parchment, and cool completely—at least 45 minutes. Frosting a warm cake will melt the buttercream.
- STEP07
In the same washed bowl, beat the softened butter until creamy. Add the sifted powdered sugar and cocoa, then the cream, vanilla, and salt. Beat until fluffy and spreadable, 2 to 3 minutes, adding cream a teaspoon at a time if it is too stiff.
- STEP08
Set one layer on a plate, spread a thick layer of buttercream on top, then stack the second layer. Frost the top and sides with an offset spatula in smooth sweeps. Let the assembled cake set for 15 minutes before slicing for the cleanest cut.
Make ahead
Bake the layers up to 2 days ahead, cool completely, wrap tightly in plastic, and hold at room temperature—wrapped layers stay noticeably moister than exposed ones. The buttercream can be made 3 days ahead and refrigerated; re-whip it at room temperature until fluffy before spreading. Assemble the finished cake up to a day in advance.
Storage
Store covered at room temperature for up to 3 days or refrigerated for up to 5 days; the crumb actually improves on day two as it settles. Bring refrigerated cake to room temperature before serving so the buttercream softens. Freeze unfrosted layers, tightly wrapped, for up to 3 months.
Variations
Sheet Cake
Pour all the batter into a greased and parchment-lined 9x13-inch pan and bake at 350°F (175°C) for 35 to 40 minutes. Frost directly in the pan for an easy potluck cake.
Cupcakes
Line two 12-cup muffin tins and fill each well two-thirds full. Bake at 350°F (175°C) for 18 to 20 minutes. Yields about 24 cupcakes.
Dairy-Free
Swap the buttermilk for 240 ml (1 cup) unsweetened soy or almond milk mixed with 1 tablespoon lemon juice, and use a plant-based butter and cream for the frosting.
Serve with
Nutrition per serving
Nutrition values are estimates based on the metric measurements. Adjust as needed.
Frequently asked
Why is the chocolate cake batter so thin?
A thin, pourable batter is the hallmark of this chocolate cake recipe and the reason the crumb turns out so moist. The boiling water blooms the cocoa and dissolves the sugar, producing a delicate, tender cake rather than a dense one. Trust the consistency—it sets up perfectly in the oven.
Can I use coffee instead of water?
Yes, and we recommend it. Hot brewed coffee intensifies the chocolate flavor without making the cake taste like coffee. Use it as a direct one-to-one swap for the boiling water.
How do I keep the cake from sticking to the pan?
Grease the pans, line the bottoms with parchment rounds, then grease and dust the parchment with cocoa. Cool the layers 15 minutes before inverting. This wet batter is prone to sticking, so the parchment is non-negotiable.
Can I make this without a mixer?
Absolutely—that is the whole point of a one-bowl cake. The batter comes together with a hand whisk in about a minute. You only need a mixer for the buttercream, and even that can be beaten by hand with a little patience.
How do I know when the cake is done?
The cakes are ready when they spring back lightly when pressed in the center and a toothpick comes out with a few moist crumbs clinging to it—not wet batter. Start checking at 30 minutes; overbaking is the fastest way to dry out any chocolate cake.
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