Ingredients
Method
For the Cake:
- Preheat the oven to 350°F. Grease three 8-inch round baking pans, line the bottoms with parchment paper, and prepare bake-even strips if using.
- Combine sugar, vegetable oil, eggs, and lemon extract in a large mixing bowl. Beat on medium speed for approximately 2 minutes until the mixture is light in color and well incorporated, scraping the bowl as needed.
- Zest two lemons into the batter and juice them to obtain 1/4 cup of juice. Add the lemon zest, juice, and sour cream to the bowl and beat until well combined.
- Mix the dry ingredients in a separate bowl. Add half of the dry mixture to the batter while beating on low speed, gradually pouring in half of the buttermilk until the flour is just incorporated.
- Add the remaining dry ingredients and buttermilk, beating until all components are thoroughly combined.
- Scrape the sides and bottom of the bowl with a spatula and stir to ensure the batter is evenly mixed.
- Toss the blueberries with 2 tablespoons of flour. Gently fold the blueberries into the batter, reserving a small handful to place on top later.
- Divide the batter evenly among the three prepared pans, using about 1 2/3 cups per pan. Top with the reserved blueberries and bake at 350°F for 20-23 minutes, rotating the pans halfway through.
- Test for doneness by inserting a toothpick into the center; it should come out clean. Remove the pans from the oven and allow the cakes to cool completely.
For the Frosting:
- Chill the mixing bowl and whisk attachment in the freezer for 5 to 10 minutes.
- Place the cold mascarpone in the chilled bowl and beat on medium-low speed. Slowly pour in the heavy cream until the mascarpone reaches a liquid consistency.
- Increase the mixing speed to high and beat until soft peaks form.
- Add the powdered sugar and vanilla extract, beating on low until incorporated, then increase to high speed and beat until stiff peaks form.
- Level the cake tops with a cake leveler. Secure the bottom layer to a cake board using a small dollop of frosting.
- Fill a piping bag with half of the whipped cream and pipe an even layer of frosting onto the cake. Spread half of the lemon curd over the filling.
- Add the second cake layer and repeat the frosting and curd application. Place the final cake layer on top.
- Fill any gaps between layers with frosting and apply a thin crumb coat. Smooth the exterior with an offset spatula, ensuring any frosting contaminated with cake crumbs is not returned to the main batch.
- Frost the top and sides of the cake using an offset spatula and remove excess with an icing smoother. Optionally, create texture by gently pressing the spatula against the sides while rotating the cake.
- Pipe decorative florets on top using the remaining frosting and a large open round tip. Garnish with lemon slices and blueberries, and keep the cake refrigerated.
Nutrition
Notes
Berry Prep: I always toss my blueberries in a little flour before folding them in because it prevents them from sinking to the bottom of the pans during the bake.
Frosting Success: I've learned the hard way that you must keep your mascarpone and heavy cream ice cold to get those stiff, beautiful peaks without the mixture curdling.
Assembly Tip: When I'm layering the lemon curd, I make sure to pipe a sturdy ring of frosting around the edge of the cake layer first to act as a dam so the curd stays tucked inside.
Storage Advice: Because of the fresh cream and mascarpone, I always store this cake in the refrigerator and find it actually tastes even better after the flavors meld for a few hours.
Ingredient Temperature: I make sure my eggs and buttermilk are at room temperature before I start mixing because it helps the batter emulsify perfectly for a much lighter crumb.
Make Ahead Secret: I often bake the cake layers a day early, wrap them tightly in plastic wrap, and chill them overnight because cold cakes are much easier to level and frost without crumbling.
Flavor Boost: I like to rub the lemon zest into the granulated sugar with my fingertips until it's fragrant and damp, which releases the natural oils and gives the cake a much deeper citrus punch.