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.

overhead of a slice of lemon cake on a plate with a whole cake in the background.

Lemon Berry Mascarpone Cake

I am swooning over this Lemon Blackberry Cake. It’s similar to my lemon blueberry cake, but with different berries. And it is, quite literally, perfection. It’s a homemade, lemon layer cake with fresh blackberries baked right in. Nestled between each layer is a generous layer of the perfect mascarpone whipped cream and lemon curd.

If you’ve never had mascarpone whipped cream, I suggest you try it immediately. It’s like regular whipped cream, but thicker, more of a mousse. Its subtle flavor complements literally whatever you pair it with!

So, next time someone asks for a lemon birthday cake or you’re just craving a lemon or fruity dessert, you’ll know exactly what to make!

side view of a lemon cake with a slice cut out topped with fresh blackberries and lemon.

Key Ingredients

Oil – Make sure you’re using a neutral oil such as vegetable oil.
Lemons – We’ll need both the zest and the juice to give our cake the perfect lemon flavor. If you don’t know how to zest a lemon, here’s a helpful tutorial for you (you don’t even need a zester!).
Lemon or Vanilla Extract – If you want the extra zing, go with lemon extract.
Sour Cream – If you don’t have sour cream, plain Greek yogurt can be used in its place.
Buttermilk – You could also use milk, but the texture won’t be quite as moist and tender. Otherwise, you can try this simple homemade buttermilk.
Blackberries – We’re mixing fresh blackberries directly into the cake batter, then also using them for garnish.
Mascarpone cheese- Check your grocery store, usually in the specialty cheese section. This can be an expensive ingredient, but my preferred brands are Belgioioso, Trader Joes, and Vermont Creamery.

How to Make Lemon Cake with Mascarpone Frosting

Step 1: Make the Cake

Prepare the pans: Grease and flour three 8-inch baking pans, and I recommend lining the bottom with parchment paper.
Mix the wet ingredients: In a bowl, mix together sugar, oil, eggs, and lemon extract and beat until it’s well combined. Then add in the lemon zest and sour cream, then mix until combined.
Add the dry ingredients and buttermilk: In a separate bowl, whisk together the dry ingredients. Add the dry ingredients to the wet ingredients, alternating with the buttermilk and lemon juice. Mix on low speed until the flour is combined. Give the batter a good stir with a spatula.
Add the berries: Toss the berries with a little bit of flour, then gently fold half of them into the cake batter.
Bake and cool: Divide the batter evenly between three 8-inch baking pans, then top with remaining blackberries. Bake until a toothpick comes out clean. Cool completely.

Step 2: Make the Frosting

Some people do have issues making mascarpone whipped cream. I recommend reviewing the full tutorial (linked above) before beginning. It’s not meant to be stable like buttercream, it’s still a whipped cream. It is however, much thicker and easier to work with than traditional whipped cream.

Chill the bowl. Place a mixing bowl and whisk attachment in the freezer to chill for 5-10 minutes.
Beat the mascarpone: The key to a smooth textured whipped cream is to slowly bring the mascarpone cheese to a liquid consistency. Start by beating it on a low speed while slowly pouring in the heavy cream until it reaches a liquid consistency (about 1/4-1/2 cup of cream).
Whip until stiff peaks. Once it’s more of a liquid consistency, add the remaining heavy cream and increase the mixer to high speed, beating until soft peaks form. Add in powdered sugar and lemon extract and beat until stiff peaks form.

Step 3: Assemble

Level the cakes: If you find the cakes have domed, use a cake leveler to cut the domes off the top of each layer. However, the tops may not be completely flat due to the berries. This cake is quite moist, so you want to avoid ripping the outside.
Frost and fill: Place a dollop of frosting on a cake board, then place the bottom layer on top. Use a piping bag to pipe a layer of frosting around the edge and over the top of the first layer, then spread half the lemon curd on top. Add the second layer of cake, repeat with the frosting and lemon curd, then add the final layer on top. I like to invert the top layer so it’s nice and flat on top. If you want to see how I do this, I included some step-by-step photos of the process in my Lemon Raspberry Cake recipe.
Decorate and chill: Top with remaining frosting then garnish with extra berries. I do recommend chilling the cake before serving to allow the frosting to rechill.

side view of a slice of lemon cake on a blue and white plate.

Why is My Lemon Cake Not Fluffy?

This cake is more dense than it is light and fluffy, but if it’s extra dense and flat, there could be a couple of reasons for that.

Use fresh baking powder. The expired baking powder won’t do what it’s supposed to do which is create a lighter, fluffier texture. Make sure it’s fresh before adding it to the batter.
Don’t substitute ingredients. Wherever possible, I do not recommend making substitutions. True buttermilk will always produce better results than a homemade substitute.
Properly measure the flour. If you are not weighing ingredients, make sure to use the fluff, spoon and level method to measure the flour. Scooping your cup directly into the flour is the surest way to add too much flour, resulting in a dense cake.
Don’t over-mix the batter. Over-mixing the cake batter can cause a dry, dense texture. Mix everything only until just combined and avoid mixing too much for the best results.

Recipe Tips

Toss the berries with flour. Coating them in a light layer of flour can help prevent them from sinking in the batter as the cake bakes depending on the size of the berries.
Use bake-even strips. Bake even strips prevent the edges of the cake from cooking too quickly which, in turn, prevents the cake from rising in the middle. The less you have to cut off the top, the better!
To fill your cake, I suggest filling a piping bag with frosting to ensure an even thickness throughout.

a partially eaten slice of layer cake with a bite on a fork.

Preparation and Storage

The best way to prep your lemon cake ahead of time is to bake the lemon cake, but wait to add the frosting. Regardless of how you store them, be sure the cakes are completely cooled.

Frosting: I do not recommend preparing the frosting in advance, it’s best when prepared fresh and directly frosted onto the cake.

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.

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.