A lemon layer cake filled with lemon curd and lightly frosted with mascarpone buttercream. It’s the perfect cake to welcome the the start of Spring.
The changing of the seasons brings so much hope and excitement. I’m looking forward to all the spring greens, beets, and rhubarb about to hit the markets. While we wait for strawberries to make their appearance, let’s continue with the citrus love.
For the most part, lemons are harvested all year long (especially in Southern California). I’ve always associated lemon and other citruses as winter fruits.
During cold days, lemons are my go-to. Be in to a flavor a cake, season meats and veggies, or squeezed in some hot tea, fresh lemons are a kitchen staple.
Lemon Layer Cake
This lemon cake recipe is special to me. It’s the same one I used in this rosemary lemon cake – which is one of the cake layers I made for our wedding cake! Instead of infusing the cake with any spices or herbs, I kept this cake clean. I wanted the lemon to shine.
The cake is frosted with a rather light feeling buttercream made from a mixture of unsalted butter and mascarpone cheese. You might be familiar with mascarpone cheese. It is best known for it’s role in tiramisu. The mascarpone adds a nice soft, creaminess to the otherwise thick American buttercream.
How to assemble and fill lemon cake:
This recipe makes three 8-inch cake layers. To assemble the cake, start with one cake round. Spread a thin layer of mascarpone buttercream on top of cake. Then pipe a small border of mascarpone buttercream along the perimeter of the cake round.
If desired, pipe a double border like I did in the image above. This border will serve as a barrier when you fill the cake with lemon curd.
I used store-bought lemon curd from Trader Joe’s. If you’ve like a homemade version, I suggest these recipes: lemon curd from Baking a Moment, lemon curd from Sally’s Baking Addiction, or lemon curd from Epicurious.
Carefully spread a layer of lemon curd within the buttercream boundaries. I used about two tablespoons. You’ll do this for the first two layers of the cake. The final (third) top layer will not have any lemon curd.
Once the cake has been filled, lightly frost the outside of the cake with the remaining mascarpone buttercream. When frosting the cake, you may notice the mascarpone buttercream start to separate. Do not worry. Let the frosted cake chill in the fridge for 15 minutes or so to allow the buttercream to harden and come back together.
Tips on slicing and portioning out cake:
I decorated the finished lemon layer cake with a simple piped border using an 18mm Ateco 829 star piping tip. This serves two purposes:
- The piped topping gives the cake texture and dimension. It also allows the confetti sprinkles something to attach to.
- The piped decor serves as a portioning guide. I cut the cake slices based on the piped stars. This way everyone gets an equal sized cake slice!
Lemon Layer Cake with Mascarpone Buttercream
Yield: three layer 8-inch cake
- 2 1/4 cups all-purpose flour
- 1 teaspoon baking powder
- 1 teaspoon baking soda
- 1/2 teaspoon fine sea salt
- 3/4 cup unsalted butter, softened
- 1 1/4 cup granulated sugar
- 3 large eggs, room temperature
- 1/3 cup sour cream, room temperature
- 2/3 cup whole milk, room temperature
- 5 Tablespoons fresh squeezed lemon juice
- 1 Tablespoon finely grated lemon zest
- 1/4 cup store-bought, high-quality lemon curd (to fill cake)
- 1 1/4 cup unsalted butter, softened
- 4 1/2 cups confectioners' sugar
- 1 teaspoon finely grated lemon zest
- 2 teaspoons fresh squeezed lemon juice
- 1/4 teaspoon fine sea salt
- 8 oz mascarpone cheese
Preheat oven to 350 degrees F. Line three 8-inch cake round pans with parchment paper. Lightly grease and set aside.
In a large bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, cream butter. Add sugar and whip until smooth. Add eggs and continue to mix on medium speed until incorporated. Add sour cream and mix. Scrape down bowl as needed to ensure thorough mixing.
Add flour mixture in three additions, alternating with milk. Begin and finish with flour mixture. Add lemon juice and lemon zest and mix until well incorporated.
Divide batter evenly among the three prepared cake pans. Level batter using a mini offset spatula, or the back of spoon. Bake for 30-35 minutes until a toothpick inserted in center of cake comes out clean. Let cake cool in pan for 5 minutes, then run a mini offset spatula around the cake and unmold. Let cake cool to room temperature on wire rack.
In the bowl of a stand mixer fitted with a paddle attachment, beat butter, confectioners' sugar, lemon zest, lemon juice, and salt until smooth. Scrape down bowl as needed to ensure thorough mixing.
Add mascarpone and mix until just combined. If buttercream is too thick, add 1 tablespoon of milk (half & half, or heavy cream) and mix until smooth.
Fit a decorating bag (piping bag) with a small round tip. Fill the bag with about 1/2 cup of buttercream. Set aside.
If necessary, level cake layers. Place one cake round on a cake turntable. Spread a thin layer of buttercream on cake using a small offset spatula. Using the filled piping bag, pipe a small border of mascarpone buttercream along the perimeter of the cake round. This will serve as a barrier when you filled the cake with lemon curd.
Add about two tablespoons of lemon curd to fill the buttercream boundaries. Place second cake layer on top. Repeat filling cake layer with buttercream and lemon curd. Place the final third layer on top. This layer will not have lemon curd
Spread buttercream around the cake to create a "crumb coat" layer to seal in any crumbs. Chill cake in the fridge for 15-20 minutes to set frosting. If desired, generously coat the chilled cake with additional buttercream. Chill cake if not serving immediately.
Use an 18 mm star piping tip to pipe a border along the top layer of the cake. Decorate cake with confetti sprinkles as desired. Let chilled cake sit at room temperature for at least 20 minutes before serving to allow cake to soft.
Lemon cake can be baked ahead of time. Allow to cool to room temperature before wrapping in plastic wrap. Can be stored in the freezer and used at a later time. Simply allow cake to defrost at room temperature before use.