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It’s the weekend and you’re craving a bakery-style blackberry coffee cake that’s soft and plush, with a buttery vanilla crumb, pockets of jammy berries, and a thick brown butter streusel topped with melting powdered sugar. That’s exactly what I made last weekend, and this blackberry coffee cake absolutely hit the spot. It deserves a place in your baking plans.It’s the kind of cake that feels right at home next to a hot cup of coffee. Cozy, generous, and quietly impressive. The secret? Browning the butter for both the cake and the streusel. It adds a warm, nutty depth that makes this taste like something you’d order at your favorite café. Plus, thanks to sour cream in the batter, this coffee cake stays soft and tender, never dry. If you’re planning a weekend bake, be sure to also try my blueberry coffee cake and brown butter coffee cake with brown butter vanilla glaze.

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Why You’ll Love This Blackberry Coffee Cake made with Streusel Topping

• Made with brown butter for deeper flavor
• Soft, tender crumb thanks to sour cream and milk
• Jammy blackberry layer that stays juicy, not watery
• Thick streusel topping with crisp edges and soft pockets
• Perfect for brunch, holidays, or make-ahead baking

Ingredients to make Blackberry Coffee Cake

Cake Batter

• 1/2 cup (113g) unsalted butter
• 1/2 cup (100g) granulated sugar
• 1/4 cup (55g) light brown sugar
• 2 large eggs
• 1 large egg yolk
• 1 tablespoon vanilla extract
• 1/2 cup (120g) sour cream
• 1/4 cup (60g) whole milk
• 1 1/2 cups (180g) all-purpose flour
• 1 1/2 teaspoons baking powder
• 1/4 teaspoon baking soda
• 1/4 teaspoon salt

Jammy Blackberries

• 2 cups (313g) blackberries
• 2 tablespoons granulated sugar
• 1 teaspoon lemon juice
• 1 teaspoon cornstarch
• 1 teaspoon cold water

Brown Butter Streusel

• 6 tablespoons (85g) unsalted butter
• 1/2 cup (110g) light brown sugar
• 1/4 cup (50g) granulated sugar
• 1 cup (120g) all-purpose flour
• 1/2 teaspoon vanilla extract
• Pinch of kosher salt
• Zest of 1/2 lemon (optional)

Topping

• 1/4 cup (30g) powdered sugar, for dusting

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How to Make Blackberry Coffee Cake with Brown Butter

1. Prepare the Blackberry Layer

In a saucepan, combine blackberries, sugar, and lemon juice. Cook over medium heat until berries soften and release their juices.

Stir cornstarch with water, then add to the pan. Cook 1 to 2 minutes until thick and jammy.

When you drag a spoon through the mixture, it should leave a clear streak on the bottom of the pan that slowly fills back in. This means the filling is thick enough to stay jammy in the cake instead of soaking into the batter.

Set aside to cool or in the fridge.

(You can also make this the night before.)

2. Brown the Butter

In a light-colored saucepan, melt the butter over medium heat. Cook until it foams, then turns golden with brown specks and smells nutty, about 5 to 7 minutes.

Pour into a heatproof bowl and let cool until warm but not hot.

You’ll use this for both the cake and the streusel. First time browning butter? Check out these tips in my how to brown butter post.

3. Make the Streusel

In a bowl, mix brown sugar, granulated sugar, flour, salt, and lemon zest.

Pour in the portion of browned butter for the streusel and the vanilla. Mix until clumpy and crumbly. For best texture you will have to use your hands to press everything together creating large and small clumps.

Refrigerate the streusel mixture while you make the batter.

4. Make the Cake Batter

Preheat oven to 350°F (175°C). Line a 9-inch round pan with parchment.

In a large bowl, whisk remaining brown butter, granulated sugar, and brown sugar.

Whisk in eggs and yolk until glossy. Add vanilla, sour cream, and milk.

In a separate bowl, whisk flour, baking powder, baking soda, and salt.

Fold dry ingredients into wet until just combined. Do not overmix.

5. Assemble

Spread about 3/4 of the batter evenly in the pan.

Spoon the cooled blackberry mixture over the batter and gently swirl.

Carefully spread the remaining batter over the jam. It’s okay if some mixing happens.

Sprinkle streusel generously over the top.

6. Bake

Bake for 40 to 45 minutes, until a toothpick inserted in the center comes out with a few moist crumbs.

Let the cake cool in the pan for at least 30 minutes to allow the crumb to set. Then remove and transfer to a cooling rack to cool completely before slicing for clean cuts.

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Pro Tips for the Best Blackberry Coffee Cake

Use Room Temperature Ingredients

Cold eggs or sour cream can cause the batter to split. Let everything sit out 30 minutes before baking.

Don’t Skip Cooling

The blackberry layer sets as it cools. Cutting too early makes it messy.

For Extra Bakery Texture

Chill the assembled cake for 15 minutes before baking. This helps the streusel hold its shape.

Fresh or Frozen Berries?

Both work. If using frozen, don’t thaw. Add directly to the pan.

Variations

• Blueberry Coffee Cake: Swap blackberries for blueberries
• Lemon Blackberry: Add lemon zest to batter
• Almond Blackberry: Add 1/2 teaspoon almond extract
• Glaze Instead: Drizzle with lemon glaze instead of powdered sugar

Storage & Make-Ahead

• Room temperature: 2 days, covered
• Refrigerator: Up to 5 days
• Freezer: Wrap tightly, freeze up to 2 months

Warm slices briefly before serving for best texture.

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Frequently Asked Questions

Can I skip browning the butter?

Yes, but you’ll lose flavor. Brown butter adds depth that makes this cake special.

Why use both sour cream and milk?

Sour cream adds richness. Milk keeps the crumb light. Together, they make the cake tender but not dense.

Can I make this in a 9×13 pan?

Yes. Double the recipe and bake 50 to 55 minutes.

My streusel melted. What happened?

It was likely too warm. Chill it before topping for better crumble.

Can I reduce the sugar?

You can reduce each sugar by about 2 tablespoons, but don’t cut more or texture will suffer.

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Other Coffee Cake Recipes to try: 

• ‍Brown Butter Cinnamon Coffee Cake with Brown Butter Vanilla Glaze
• ‍Blueberry Coffee Cake
• Brown Butter Pecan Coffee Cake with Salted Brown Butter Maple Icing

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