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overhead of a slice of lemon blackberry cake with mascarpone frosting on a plate.

Lemon Blackberry Cake

5 Stars 4 Stars 3 Stars 2 Stars 1 Star 5 from 11 reviews
  • Author: Julianne Dell
  • Prep Time: 30 minutes
  • Cook Time: 28 minutes
  • Total Time: 58 minutes
  • Yield: 10-12 slices
  • Category: Cake
  • Method: Baked
  • Cuisine: American


This Lemon Blackberry Cake is a moist lemon cake that’s loaded with fresh blackberries and layered with mascarpone whipped cream and lemon curd. It’s perfectly moist, deliciously dense, and the perfect blend of sweet and tangy.


For the cake:

  • 2 cups (380g) granulated sugar
  • ½ cup (118 ml) vegetable oil
  • 3 large eggs, at room temperature 
  • 2 lemons- zested and juiced 
  • 1 teaspoon Lemon (or vanilla) extract
  • ½ cup (118 ml) sour cream, at room temperature 
  • 2 ½ cups (350 g) all-purpose flour, sifted
  • 3 teaspoons (11.2 g) baking powder
  • 1 teaspoon (5 g) salt
  • 1 cup buttermilk (236 ml) (or milk), at room temperature 
  • 1/4 cup (59ml) fresh lemon juice
  • 12 ounces blackberries, washed and dried
  • 2 tablespoons (15g) all-purpose flour

For the frosting:

  • 2 ¼ cups (532ml) heavy whipping cream, cold
  • 1 cup (130g) powdered sugar
  • 1 teaspoon (5ml) lemon extract 
  • 16 ounces mascarpone cheese, cold
  • 1 jar (10 ounces) Lemon Curd


For the Cake: 

  1. Preheat the oven to 350°F. Prepare three 8-inch round baking pans, line the bottom with parchment paper, grease the sides and dust with flour.
  2. In a large mixing bowl, combine the sugar, vegetable oil, eggs, and lemon extract. Beat on medium speed until the eggs and oil are well incorporated, scrape down the bowl as needed. Next, add the lemon zest and the sour cream and beat until well combined.
  3. After sifting the remaining dry ingredients, gradually add half of the dry mixture to the batter, followed by half of the liquid ingredients (buttermilk and lemon juice). Mix on low speed until all ingredients are incorporated. Then, use a spatula to thoroughly mix the batter, ensuring even distribution of ingredients
  4. Toss the blackberries with 2 tablespoons of flour. If the blackberries are large, cut them in half, then gently fold the blackberries into the batter with a spatula.
  5. Divide the batter evenly between the three pan, about 1 ¾ cups of batter per pan. Bake at 350°F for 28-32 minutes.  Test the cake for doneness by inserting a toothpick into the center of the cake. If the toothpick comes out clean, the cake is done. Remove from the oven and allow to cool completely.

For the Frosting: 

  1. Place the mixing bowl and whisk attachment in the freezer for 5 to 10 minutes to chill.
  2. Spoon the cold mascarpone whipped cream into your bowl and beat on a medium-low speed while slowly pouring in about 1/4 cup of the heavy cream, allowing the mascarpone cheese to turn to a liquid consistency. Then add the remaining heavy cream and increase the mixing speed to high, beating it until soft peaks form.
  3. Next, add the powdered sugar and lemon extract, beating on low until sugar to incorporate, then continue beating at high speed until stiff peaks form.

To Assemble 

  1. Use a cake leveler to cut the domes off the top of the cake if needed. Place a dollop of frosting on the cake board and place the bottom layer of cake on top of that.
  2. Place half of the whipped cream in a large piping bag fitted with a large open round tip, or simply cut off the end of the piping bag. Pipe a layer of frosting starting from the outside edge and working towards the middle. Spread evenly with a knife if needed. Then spread half of the lemon curd over the mascarpone frosting.
  3. Add the second layer of cake and repeat the above steps using all of the remaining lemon curd. Next, add the final layer of cake on top.
  4. Use the piping bag to fill in any gaps between the layers and to create a crumb coat. Using an offset spatula or icing smoother, wipe away the excess frosting, leaving you just enough to coat the outside of the cake. Do not mix your crumb-coating frosting back into your icing if it has cake debris in it.
  5. Proceed to frost the top and sides of the cake using the offset spatula with the remaining frosting. Garnish with leftover blackberries. 



Wherever possible, I do not recommend making substitutions, but in a pinch the below will work. 

  • Sour cream- use plain non Greek yogurt. 
  • Buttermilk- Can be made using lemon juice or vinegar. Here’s the quick homemade buttermilk 
  • Lemon extract– sub with vanilla if needed
  • Frozen berries: Note that I have not tested this with frozen blueberries but it should work. Frozen berries may have more moisture than fresh. Toss in the batter when frozen and do not coat in flour

Make Ahead and Storage Instructions

  • Unfrosted cake layers: In you plan to frost within 48 hours, store these in an airtight container at room temperature. Do not stack them together as the layer are quite moist and they will stick. To freeze the layers, wrap it in plastic wrap followed by foil, and freeze them for up to 2 months. When you’re ready to serve, thaw to room temperature then frost and serve.
  • Frosting: I do not recommend making this in advance. Prepare and use right away. 
  • How to Store a Frosted Cake: An assembled lemon berry mascarpone cake must be stored in an airtight container in the fridge. It will last for for 3-4 days. For best results, you may want to place a piece of plastic wrap on the cut edges to prevent them from drying out.


  • Serving Size: 1 slice
  • Calories: 672
  • Sugar: 60.1g
  • Sodium: 370mg
  • Fat: 32.6g
  • Saturated Fat: 21.1g
  • Carbohydrates: 89.9g
  • Fiber: 2.4g
  • Protein: 8.4g
  • Cholesterol: 112.6mg