Name: One-Bowl Buttermilk Chocolate Cake Recipe
Prep time: 15 min
Cook time: 35 min
Total time: 50 min
Ingredients: 1 3/4 cups all-purpose flour; 3/4 cup unsweetened cocoa powder; 1 1/2 tsp baking powder; 1 tsp baking soda; 1/2 tsp salt; 1 3/4 cups granulated sugar; 1 cup buttermilk; 1/2 cup vegetable oil; 2 large eggs; 2 tsp vanilla extract; 1 cup hot brewed coffee; 1/2 cup unsalted butter, softened; 2 cups powdered sugar; 1/2 cup unsweetened cocoa powder; 2-3 tbsp buttermilk; 1 tsp vanilla extract

A deeply chocolatey buttermilk cake that comes together in one bowl and stays moist for days.

The crumb is tender, and a simple chocolate frosting finishes it off.

Why This Cake Works

This cake has the kind of rich, chocolate flavor that only really blooms when you use hot coffee and tangy buttermilk. The result is a soft, dark crumb that never turns dry.

The batter comes together in a single bowl, no mixer required for the cake itself. You whisk the dry ingredients, add the wet ones, and stir in the hot coffee, and it’s oven-ready in under fifteen minutes.

The frosting is a straightforward buttercream with buttermilk for a little tang that cuts the sweetness. It whips up while the cake cools, and together they make a dessert that feels far fancier than the effort suggests.

Ingredients

1 3/4 cups all-purpose flour: spooned and leveled, not scooped
3/4 cup unsweetened cocoa powder: natural or Dutch-process both work
1 1/2 tsp baking powder
1 tsp baking soda
1/2 tsp salt
1 3/4 cups granulated sugar
1 cup buttermilk: at room temperature
1/2 cup vegetable oil: any neutral oil
2 large eggs: at room temperature
2 tsp vanilla extract
1 cup hot brewed coffee: or hot water, but coffee deepens the chocolate
For the frosting:
1/2 cup unsalted butter, softened: a full stick, at room temperature
2 cups powdered sugar: sifted if lumpy
1/2 cup unsweetened cocoa powder: sifted with the sugar
2-3 tbsp buttermilk: or regular milk, to thin
1 tsp vanilla extract

Variations / Substitutions

No buttermilk: stir 1 tbsp lemon juice or vinegar into 1 cup milk, let sit 5 minutes, then use as directed.
No coffee: replace with an equal amount of hot water. The chocolate flavor will be a little less deep.
Melted butter instead of oil: use the same amount, but the cake will be slightly less moist after a couple of days.
Richer frosting: add 2 oz melted unsweetened chocolate and reduce the buttermilk to 1 tbsp.
Layer cake: divide batter between two greased 8-inch round pans and reduce bake time (see table below).

For a simpler chocolate snack cake without frosting, try our Chocolate Snacking Cake.

How to Make One-Bowl Buttermilk Chocolate Cake

Step 1: Whisk the Dry Ingredients

Preheat your oven to 350°F (180°C) and grease a 9×13-inch metal baking pan. In a large bowl, whisk together the 1 3/4 cups flour, 3/4 cup cocoa powder, 1 1/2 tsp baking powder, 1 tsp baking soda, and 1/2 tsp salt until no dark or light streaks remain. Whisk in the 1 3/4 cups sugar until everything looks evenly speckled.

The cocoa will likely have small lumps. Rubbing them out with your fingers against the whisk helps, or just press them against the side of the bowl. You want a uniform, pale brown powder before adding anything wet.

Step 2: Combine the Wet Ingredients

Pour the 1 cup buttermilk, 1/2 cup vegetable oil, 2 large eggs, and 2 tsp vanilla extract straight into the bowl of dry ingredients. Beat with an electric mixer on medium speed for about 1 minute, or whisk vigorously by hand for 2 minutes, until the batter turns glossy and smooth. Stop as soon as no streaks of flour are visible.

The oil makes the batter feel a little thicker than a butter-based cake batter, which is what gives the finished crumb its soft, tender texture. The mixture will be thick but still pourable, and it should pull away cleanly from the whisk.

Step 3: Bake the Cake

With the mixer on low, or using a spatula, slowly pour the 1 cup hot coffee into the bowl. Stir just until the liquid disappears and the batter thins out. It will look quite loose, almost like thin pancake batter. Pour it into the prepared pan and tap the pan gently on the counter twice to level it. Bake for 30 to 35 minutes, until a toothpick inserted in the center comes out clean or with a few moist crumbs clinging to it.

The cake will start pulling away from the sides and spring back when pressed lightly in the middle. Let it cool in the pan for 10 minutes, then turn it out onto a wire rack to cool completely before you frost it. A warm cake will melt the frosting, so waiting is key.

Step 4: Whip the Frosting

In a medium bowl, beat the 1/2 cup softened butter with an electric mixer until creamy, about 1 minute. Sift the 2 cups powdered sugar and 1/2 cup cocoa powder into the bowl. Add 2 tbsp buttermilk and 1 tsp vanilla extract. Start the mixer on low so the sugar doesn’t fly everywhere, then increase to medium-high and beat for 2 to 3 minutes, until the frosting lightens in color and looks fluffy. If it’s too stiff, beat in the extra 1 tbsp buttermilk a little at a time.

The frosting should hold a soft peak when you lift the beaters and taste balanced: sweet, deeply chocolatey, with a faint tang from the buttermilk. It spreads smoothly and sets with a slight crust after a few minutes.

Step 5: Frost and Slice the Cake

Once the cake is completely cool, dollop the frosting on top and spread it in an even layer with an offset spatula or the back of a spoon. Slice into squares and serve at room temperature.

The slices show a tight, dark crumb with a clean edge, and the frosting stays creamy without sliding. Any leftover pieces can sit out, covered, for a day and still taste freshly baked.

Tips for a Perfect Chocolate Cake

Bring cold ingredients to room temperature: cold eggs or buttermilk can make the batter seize slightly and cause a denser crumb. Leave them on the counter for 30 minutes before you start.
Line the pan for easy lifting: grease the pan, then fit a rectangle of parchment paper across the bottom with some overhang. Once the cake cools, use the overhang to lift it out in one piece.
Stop mixing once the coffee goes in: over-stirring at that stage can make the cake a little tough. Just stir until you no longer see milky streaks and pour it right into the pan.
Try a layer cake instead: divide the batter between two greased 8-inch round pans and bake for 25 to 30 minutes. Frost between the layers and on top.

Bake times by pan:

Pan Size	Bake Time	Doneness Cue
9×13-inch metal	30-35 mins	toothpick clean
Two 8-inch rounds	25-30 mins	toothpick clean
9-inch square	30-35 mins	toothpick clean

Storing Leftover Cake

Room temperature: keep the frosted cake covered for up to 2 days. The frosting sets firm enough that a cake dome or inverted large bowl works.
Refrigerate: in warm weather, refrigerate covered for up to 4 days. Let slices come back to room temperature before serving so the frosting softens.
Freeze: wrap the unfrosted cake layers tightly in plastic and freeze for up to 3 months. Thaw overnight in the fridge, then frost as directed.

Frequently Asked Questions

Can I use natural cocoa powder instead of Dutch-process?

Yes, either works. Natural cocoa will give a slightly earthier, more acidic note, while Dutch-process tastes smoother and darker. The recipe handles both without adjusting the leavening.

Why did my cake turn out dry?

Overbaking is the most common cause. Even an extra few minutes can dry out the crumb, so check at the earliest time. Also make sure to spoon flour into the measuring cup and level it rather than scooping straight from the bag.

Can I make this gluten-free?

Yes. Use a quality 1:1 gluten-free flour blend that contains xanthan gum. The texture will still be moist, just a little more tender and fragile when slicing.

Does the coffee make the cake taste like coffee?

No, the coffee only deepens the chocolate flavor without any coffee taste. You can use hot water instead and still get a good chocolate cake, just not quite as intense.