My lemon blackberry cake is a fresh, fruity layer cake made with soft lemon cake, silky blackberry curd, and whipped blackberry buttercream. Each bite is the perfect balance of tart, sweet, and buttery richness — the lemon brings brightness while the blackberry curd adds deep, jammy flavor.
If you love this pairing, you'll want to try my lemon blueberry mascarpone cake, and for another bright, sweet-tart bake, my strawberry rhubarb crumb bars are a favorite.
Quick Look: Lemon Blackberry Cake
⏱️ Ready In: About 1 hour 25 minutes, plus chilling
🔥 Bake Time: 23–25 minutes at 350°F
🍽️ Makes: 12 servings (three-layer 8-inch cake)
✨ Calories: Approximately 755 per serving
🥄 Main Ingredients: Lemon, blackberries, blackberry curd, blackberry buttercream
🌿 Dietary Info: Vegetarian
💛 Why You'll Love It: Bright lemon layers, jammy homemade blackberry curd, and whipped blackberry buttercream — a stunning, tangy-sweet centerpiece cake.
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Why You'll Love This Recipe
- A showstopping centerpiece. Vibrant purple curd and frosting make it an instant table centerpiece, like my sourdough funfetti layer cake and my easy brown butter bourbon peaches and cream cake.
- Bright and balanced. Tart lemon, jammy blackberry, and buttery frosting in perfect harmony.
- Homemade blackberry curd. Silky, seedless, and deeply fruity — the same homemade-curd magic as my lemon curd muffins.
- Soft, tender lemon layers. A sour cream lemon cake that bakes up moist and fluffy.
- Perfect for celebrations. Easter, Mother's Day, bridal and baby showers, birthdays, or just a sunny weekend bake. Pair it with my matcha cupcakes for a show stopping summer dessert spread!
Jump to:
- Quick Look: Lemon Blackberry Cake
- Why You'll Love This Recipe
- Ingredients You'll Need
- Easy Substitutions & Variations
- How to Make Lemon Blackberry Cake
- Expert Tips
- What Makes This Recipe Special?
- Lemon Blackberry Cake FAQs
- Lemon Blackberry Cake Troubleshooting Guide
- Storage
- Other Fruit-Filled Recipes to Consider
- Lemon Blackberry Cake
Ingredients You'll Need
For the blackberry curd
- Fresh blackberries: Pureed and strained into a seedless base — the same berry you'll find in my bakery-style banana blackberry muffins.
- Egg + egg yolks: Thicken the curd into a silky filling.
- Unsalted butter: For richness and shine.
- Granulated sugar + lemon juice: Sweeten and brighten.
For the lemon cake
- Granulated sugar + unsalted butter: Creamed for a light, fluffy crumb.
- Sour cream: Keeps the layers moist and tender.
- Vanilla + lemon zest: The lemon zest is where most of the citrus flavor lives.
- Egg whites: For a soft, pale, fine crumb.
- All-purpose flour, baking powder + salt: The structure and lift.
- Milk + water: Loosen the batter to the right consistency.
For the blackberry buttercream
- Fresh blackberries, lemon juice + sugar: Cooked into a reduction that flavors and colors the frosting.
- Powdered sugar + unsalted butter: Whipped into a smooth, pipeable buttercream.
See the recipe card for quantities.
Easy Substitutions & Variations
- Dairy-free: Use a high-fat non-dairy milk and plant-based butter.
- Lemon mascarpone filling: Swap the curd for a fluffy lemon mascarpone cream for a softer, mousse-like layer.
- Single-layer version: Bake in a 9x13 pan, top with buttercream, and drizzle the curd over the top for a casual, crowd-friendly cake.
- Mini cakes or cupcakes: Divide the batter into cupcake tins or thinner layers — perfect for gifting or tea parties.
- More lemon-berry bakes: Try the same flavors in my lemon raspberry sweet rolls, lemon raspberry cookies, or lemon blueberry cookies.
How to Make Lemon Blackberry Cake
Step 1: Reduce the Blackberry Curd
Simmer the blackberry puree until thick and jammy—it should look glossy and hold its shape like this before adding the eggs and butter.
Step 2: Finished Curd, Ready to Chill
Once the curd is fully cooked and thickened, strain it one more time if needed, then cover and chill it until completely cold.
Step 3: Prepare and Bake the Cake Layers
Mix the lemon cake batter, divide it evenly between three pans, and bake until lightly golden and a toothpick comes out with just a few crumbs.
Step 4: Make the Blackberry Reduction
Simmer blackberries, lemon juice, and sugar until thick, then strain and chill the mixture—this will flavor and color the buttercream.
Step 5: Whip the Butter
Whip the room temperature butter until pale, smooth, and fluffy—this step creates the foundation for a light and creamy frosting.
Step 6: Finished Blackberry Buttercream
Add the powdered sugar and cooled reduction to the butter, a spoonful at a time, until the color and texture are just right.
Step 7: Assemble the Layers
Spread a thin layer with raised edges of buttercream on each cake layer before adding the chilled curd to the middle—this keeps the filling neat and stable.
Step 8: Crumb Coat and Decorate
Apply a thin crumb coat, chill, then finish frosting the cake. Swirl on any leftover curd and top with fresh lemon zest before serving.
Weigh your ingredients! Using a kitchen scale ensures your measurements are accurate, which is key for consistent results in baking. It takes the guesswork out of measuring and helps your cake turn out exactly as intended every time.
Expert Tips
- Chill the curd completely. Warm curd will slide out of the layers — make it first so it has time to set.
- Build a buttercream dam. Pipe a thin border of buttercream around each layer before adding curd so the filling stays put.
- Strain twice for smooth curd. Straining out seeds and any cooked egg bits gives the silkiest texture.
- Sift the powdered sugar. A sifter keeps the buttercream smooth and easy to pipe.
- Add the reduction gradually. Mix the cooled blackberry reduction into the buttercream a tablespoon at a time until the color and consistency are just right.
What Makes This Recipe Special?
Most berry cakes rely on jam or fresh fruit; this one uses a true homemade blackberry curd, cooked down until deeply concentrated and silky, plus a blackberry reduction whipped into the buttercream. That means real, intense blackberry flavor in both the filling and the frosting, balanced by a bright, tender lemon cake. The marbled curd-and-buttercream finish makes it look as special as it tastes.
If you love lemon desserts, you're in good company on the blog. My sourdough lemon pound cake and sourdough lemon snack cake are easier, everyday ways to get that same bright citrus flavor.
Lemon Blackberry Cake FAQs
Yes — this is a great make-ahead cake. The blackberry curd and the cake layers can both be made a day or two in advance; assemble and frost when you're ready.
Yes. Thaw them and use as directed for both the curd and the reduction — they purée and strain just the same.
Straining removes the seeds and any cooked egg bits, giving you smooth, silky curd and buttercream.
Absolutely — bake in a 9x13 pan, frost the top, and drizzle the curd over for a casual version.
Whip the butter until pale and fluffy, sift the powdered sugar, and add the cooled reduction gradually so the frosting doesn't get too loose.
Lemon Blackberry Cake Troubleshooting Guide
| Problem | Cause | Fix |
|---|---|---|
| Curd too runny | Puree not reduced enough or undercooked. | Reduce the puree until very thick, then cook the curd until it coats a spoon. |
| Filling squeezed out | No buttercream dam, or curd too warm. | Pipe a buttercream border and use fully chilled curd. |
| Grainy buttercream | Powdered sugar not sifted, or butter too cold. | Sift the sugar and use properly softened butter. |
| Buttercream too loose | Too much reduction added. | Add the reduction gradually; balance with a little more powdered sugar. |
| Dense cake layers | Overmixed batter or cold ingredients. | Mix just until combined and use room-temperature ingredients. |
Storage
- Store in an airtight container in the refrigerator for up to 4 days.
- Freeze for up to 6 months: flash freeze uncovered, then wrap in plastic wrap and foil. Thaw in the fridge to keep condensation off the frosting.
Other Fruit-Filled Recipes to Consider
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Lemon Blackberry Cake
Equipment
- Kitchen scale (please weigh your ingredients)
- Stand mixer (or large mixing bowl with an electric mixer)
- medium bowl for mixing dry ingredients
- Small saucepan for making curd/jam
- Lemon zester
- Manual juicer
- 3 8-inch round cake pans
- Parchment paper rounds
- Cake decorating knife
- Cake rounds (to place the cake. You can use a large plate if you'd prefer.)
- Piping bag (optional; I didn't use one.)
- Icing tip of choice (optional; I didn't use one.)
- KitchenAid Fruit and Vegetable Strainer (optional; you can blend/smash the berries and strain through a fine mesh strainer instead)
Ingredients
Blackberry Curd
- 12 oz fresh blackberries around 3 cups
- 1 large egg
- 2 egg yolks
- 57 g unsalted butter ¼ cup
- 100 g granulated sugar ½ cup
- 22.5 g lemon juice 1.5 tablespoons
Lemon Cake
- 300 g granulated sugar 1 ½ cups
- 170 g unsalted butter room temperature (¾ cup)
- 170 g sour cream ¾ cup
- 9 g vanilla extract 2 tsp
- 8 g lemon zest 2 tablespoons from 2 lemons
- 6 egg whites (around 30g each or 180g total)
- 300 g all-purpose flour 2 ½ cups
- 18 g baking powder 4 tsp
- ½ teaspoon salt
- 180 ml milk ¾ cup
- 59 ml water ¼ cup
Blackberry Buttercream
- 8 oz fresh blackberries 300g, 2 cups
- 90 g fresh lemon juice 6 tablespoons
- 25 g sugar 2 tablespoons
- 900 g powdered sugar about 9-10 cups
- 452 g unsalted butter room temperature (2 cups)
Instructions
Make the Curd
- Make the Blackberry Puree: Blend the blackberries until smooth, then press the puree through a fine mesh strainer using a silicone spatula or spoon until you have ¾ cup of seedless puree. Discard the seeds and pulp.(For a faster process, I love using the KitchenAid fruit and vegetable strainer—it purees and strains in one step!)12 oz fresh blackberries
- Reduce the Puree: Pour the strained puree into a small saucepan and heat over low to medium heat, stirring often to prevent scorching. Let it simmer until it thickens and reduces to just over ⅓ cup—it should be very thick and jammy.
- Whisk in Remaining Ingredients: Add the lemon juice and sugar to the reduced puree and whisk until combined. Then quickly whisk in the egg and egg yolks, making sure to add them last to avoid scrambling—keep the mixture moving as you go.1 large egg, 100 g granulated sugar, 22.5 g lemon juice, 2 egg yolks
- Cook the Curd: Reduce the heat to low and continue stirring until the sugar is fully dissolved. Add the butter one tablespoon at a time, stirring until each piece is fully melted before adding the next.57 g unsalted butter
- Finish and Chill: Continue cooking and stirring the curd until it’s thick enough to coat the back of a spoon. You’ll know it’s ready when you can drag a spoon or spatula through it and the line holds without filling back in.
- Strain and Chill: For the smoothest texture, strain the curd one more time to catch any small lumps or cooked egg bits. Cover with plastic wrap (pressing it directly against the surface) and refrigerate until completely chilled.
Make the cake
- Zest the Lemons: Zest 2 lemons until you have about 2 tablespoons (or roughly 30g) of zest, then set it aside.8 g lemon zest
- Prep the Pans and Oven: Preheat your oven to 350°F. Line three 8-inch cake pans with parchment paper and lightly grease the sides—I love using precut parchment rounds for easy prep.
- Cream the Butter and Sugar: In a large bowl, beat the butter and sugar together until light, fluffy, and pale in color—this should take about 3–4 minutes with a stand or hand mixer.300 g granulated sugar, 170 g unsalted butter
- Mix in Wet Ingredients: Add the vanilla extract, sour cream, and lemon zest to the bowl and mix until everything is fully combined and smooth.170 g sour cream, 9 g vanilla extract, 8 g lemon zest
- Add Egg Whites: Gradually add the egg whites in two or three additions, mixing well after each and scraping down the sides of the bowl to keep the batter uniform and silky.6 egg whites
- Combine Milk and Dry Ingredients: In a small bowl or measuring cup, stir together the milk and water. In a separate bowl, whisk together your dry ingredients (like flour, baking powder, and salt).300 g all-purpose flour, 18 g baking powder, 180 ml milk, 59 ml water, ½ tsp salt
- Mix the Batter: Add half of the dry ingredients to the batter and mix just until incorporated. Pour in the milk and water mixture, mix again, then add the remaining dry ingredients and mix until smooth—don’t forget to scrape the bowl one last time.
- Bake the Cakes: Divide the batter evenly between your prepared cake pans and bake for 23–25 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs but no wet batter.
Make the Buttercream
- Make the Blackberry Reduction: Add the blackberries, sugar, and lemon juice to a saucepan over medium heat. Once the mixture is warm, mash the blackberries and let it simmer for about 10 minutes, stirring occasionally to prevent sticking.8 oz fresh blackberries, 90 g fresh lemon juice, 25 g sugar
- Strain and Chill: Pour the mixture through a fine mesh sieve into a bowl, pressing out as much liquid as possible and discarding the seeds and solids. Cover and chill the reduction in the fridge until fully cooled, about 2 hours.
- Make the Buttercream: In a stand mixer with a paddle attachment or a large bowl with a hand mixer, cream the room temperature butter on medium speed for 3-5 minutes, until smooth and fluffy. With the mixer on low, gradually add the confectioners’ sugar, then mix in the blackberry reduction one tablespoon at a time until the frosting reaches your desired color and consistency (I typically use about ¼ cup).452 g unsalted butter
- Adjust if Needed: If the frosting is too thick, add 1 to 2 tablespoons of milk or water to thin it out. Use immediately for the best texture and flavor.
Assemble the cake
- Level the cake layers: If needed, use a serrated knife to level the tops of each lemon cake layer so they stack evenly.
- Add a base of buttercream: Place the first cake layer on a cake stand or serving plate. Spread a thin, even layer of blackberry buttercream over the top—this will act as a barrier to keep the curd from soaking into the cake.
- Add the Curd Filling: Spoon blackberry curd on top of the buttercream and gently spread it out, staying about ½ inch away from the edges to prevent overflow.
- Repeat the Layers: Place the second cake layer on top and repeat the process: a thin layer of buttercream, followed by a layer of blackberry curd. Top with the final cake layer.
- Crumb Coat the Cake: Apply a thin layer of buttercream over the entire cake to catch any crumbs. Chill the cake in the fridge for 20–30 minutes to set the crumb coat.
- Frost the Cake: Once chilled, cover the cake with the remaining blackberry buttercream—use an offset spatula to smooth the top and sides.
- Add the Swirled Curd: Spoon small dollops of the leftover blackberry curd randomly over the frosted cake. Use the back of a spoon or a small spatula to gently swirl the curd into the buttercream for a marbled effect.
- Finish with Lemon Zest: Sprinkle fresh lemon zest over the top of the cake just before serving for a bright, citrusy finish.
Notes
- Instead of blending/mashing and straining the berries, you can also use the KitchenAid fruit and vegetable strainer—it purees and strains in one step!
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