Fudgy Blackberry Chocolate Cake (One Bowl, 1 Hour)

This blackberry chocolate cake is the kind of dessert you can stir together on a weeknight and still feel like you pulled off something special. It’s dark, fudgy, and dotted with bursts of tart blackberry in every bite.

The batter comes together in one bowl with a whisk, no mixer required. Fresh blackberries sink just enough to create jammy pockets, and a quick chocolate glaze seals the deal.

Why This Chocolate Cake Stays Moist

The combination of oil and buttermilk keeps the crumb tender for days. Unlike butter-based cakes, this one won’t dry out after a few hours.

The blackberries add more than just fruitiness. As they bake, their juices caramelize slightly, creating tiny tangy bursts that cut through the rich chocolate.

Ingredients

• 1 cup (125 g) all-purpose flour: spooned and leveled
• 1 cup (200 g) granulated sugar
• ½ cup (50 g) unsweetened cocoa powder: Dutch-processed gives the deepest color and flavor
• 1 tsp baking soda
• ½ tsp fine sea salt
• 1 cup (240 ml) buttermilk, at room temperature: or 1 cup whole milk plus 1 tbsp lemon juice, let sit 5 minutes
• ⅓ cup (80 ml) neutral oil: vegetable or canola
• 1 large egg, at room temperature
• 1 tsp vanilla extract
• 1 ½ cups (180 g) fresh blackberries, divided: toss ½ cup in a little flour to prevent sinking
• For the glaze: 4 oz (115 g) semi-sweet chocolate, chopped, ⅓ cup (80 ml) heavy cream

Variations / Substitutions

• Swap the berries: raspberries, halved strawberries, or blueberries all work. Toss with flour just like the blackberries.
• Make it dairy-free: use almond milk plus vinegar for the buttermilk, and a plant-based cream for the glaze.
• Go deeper on chocolate: add 1 tsp instant espresso powder to the dry ingredients, it won’t taste like coffee but it makes the cocoa pop.
• Skip the glaze: dust the cooled cake with powdered sugar or serve slices with a drizzle of warm chocolate sauce.

If you love this combination, try our chocolate raspberry brownies.

How to Make Fudgy Blackberry Chocolate Cake

Step 1: Mix the Dry Ingredients

Preheat the oven to 350°F (175°C). Grease a 9-inch round cake pan and line the bottom with parchment. In a large bowl, whisk together the 1 cup flour, 1 cup sugar, ½ cup cocoa powder, baking soda, and salt until no lumps remain.

The mixture should look evenly sandy. If it clumps, sift the cocoa first.

Step 2: Whisk in the Wet Ingredients

Pour in the buttermilk, oil, egg, and vanilla. Whisk until the batter is smooth and glossy, about 1 minute of steady beating. It will be thin, that’s fine.

The batter will be quite liquid, similar to a thick pancake batter. That’s what gives the cake its fudgy texture.

Step 3: Fold in the Blackberries

Toss 1 cup of the blackberries with a teaspoon of flour (this helps them stay suspended). Gently fold them into the batter with a spatula. Scrape the batter into the prepared pan. Scatter the remaining ½ cup blackberries over the top, pressing them in just slightly.

The top berries will show through the batter and become almost jammy as they bake.

Step 4: Bake the Cake

Slide the pan into the oven and bake for 30 to 35 minutes, until a toothpick inserted in the center comes out with a few moist crumbs. The cake will start to pull away from the sides.

The kitchen will smell deeply of chocolate and warm blackberries. Let the cake cool in the pan for 10 minutes, then turn it out onto a wire rack to cool completely.

Step 5: Glaze the Cake

Once the cake is completely cool, make the glaze. Heat the ⅓ cup heavy cream in a small saucepan or microwave until just simmering. Pour it over the chopped chocolate, let it sit for 2 minutes, then stir until smooth. Spoon the glaze over the top of the cake, letting it drip down the sides.

The glaze will set as it cools. If it’s too thick, thin with a little warm cream.

Step 6: Slice and Serve

Let the glaze set for about 10 minutes, then slice the cake into wedges. Serve as is or with a spoonful of whipped cream.

This cake is best the day it’s made, but it keeps well. The blackberries stay soft and juicy.

Tips for the Best Blackberry Chocolate Cake

• Pick firm berries.: Softer blackberries can turn to mush. Look for ones that are plump and dry, not leaking juice.
• Don’t overmix.: Once the wet ingredients hit the dry, whisk just until no flour streaks remain. Overbeating can make the cake tough.
• Line the pan.: Parchment on the bottom means the cake lifts out cleanly every time, no sticking.
• Let the glaze drip.: Spooning it in the center and nudging it outward gives you those cafe-style drips down the sides.

Bake times by pan:

All times are at 350°F, check with a toothpick for moist crumbs.

Keeping the Cake Fresh

• Refrigerate: store leftovers in an airtight container for up to 5 days. The glaze stays glossy even when cold.
• Reheating: a quick 15 to 20 seconds in the microwave warms a slice and softens the glaze.
• Serve cold: the cake tastes great straight from the fridge, especially on a warm day.

What to Serve With Blackberry Chocolate Cake

A scoop of vanilla ice cream or a dollop of lightly sweetened whipped cream balances the dark chocolate. Fresh blackberries on the side echo the fruit inside and add a little brightness.

Frequently Asked Questions

Can I use frozen blackberries?

Yes. Do not thaw them, just toss in a little extra flour and add 3 to 5 minutes to the bake time.

Can I make this cake gluten-free?

Absolutely. Swap in a 1:1 gluten-free flour blend, one that contains xanthan gum.

Can I skip the glaze?

Of course. A dusting of powdered sugar or a spoonful of warm chocolate sauce are both nice, lower-effort finishes.

Is this cake moist the next day?

Yes. The oil and buttermilk keep it tender, so a slice the next day is just as soft.

Fudgy Blackberry Chocolate Cake Recipe

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 35 minutes mins

Total Time 50 minutes mins

Servings: 8 servings

Calories: 385

Ingredients Method Notes

Ingredients

  

• 1 cup (125 g) all-purpose flour
• 1 cup (200 g) granulated sugar
• ½ cup (50 g) unsweetened cocoa powder
• 1 tsp baking soda
• ½ tsp fine sea salt
• 1 cup (240 ml) buttermilk, at room temperature
• ⅓ cup (80 ml) neutral oil
• 1 large egg, at room temperature
• 1 tsp vanilla extract
• 1 ½ cups (180 g) fresh blackberries, divided
• 4 oz (115 g) semi-sweet chocolate, chopped
• ⅓ cup (80 ml) heavy cream

Method

 

1. Heat oven to 350°F (175°C). Grease a 9-inch round pan and line bottom with parchment. Whisk flour, sugar, cocoa, baking soda, and salt in a large bowl.
2. Add buttermilk, oil, egg, and vanilla. Whisk until smooth and glossy, about 1 minute.
3. Toss 1 cup blackberries with 1 tsp flour, fold into batter. Scrape into pan, scatter remaining ½ cup berries on top.
4. Bake 30–35 minutes, until a toothpick comes out with moist crumbs. Cool in pan 10 minutes, then turn onto a rack to cool completely.
5. Heat cream until simmering, pour over chopped chocolate, let sit 2 minutes, stir smooth. Spoon glaze over cooled cake.
6. Let glaze set 10 minutes, then slice and serve.

Notes

If using frozen blackberries, don’t thaw; toss them with an extra 2 tsp flour and add 3–5 minutes to the bake time. The glaze can be doubled for a thicker layer.