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Blueberry Lemon Custard Cake
Prep Time
40 mins
Cook Time
25 mins
 

An extremely soft, zesty, and sweet cake, bursting with all the favorite flavors of spring. Layers of lemon custard, lemon blueberry cake, and mascarpone lemon frosting pair together to make one of the most satisfying cakes you’ll ever try.

Course: Dessert
Cuisine: American
Keyword: blueberry layer cake, lemon cake
Servings: 10
Author: Jackie
Ingredients
Lemon Custard
  • 2 eggs beaten
  • 1 tablespoon lemon zest
  • ¼ cup granulated sugar
  • ⅔ cup fresh lemon juice about 3 lemons
  • 1 tablespoon butter
Lemon Blueberry Cake
  • 1 cup unsalted butter room temperature
  • ½ cup vegetable oil
  • 2 ½ cups granulated sugar
  • 5 large eggs room temperature
  • 2 teaspoons vanilla extract
  • 1 tablespoon lemon zest
  • 2 tablespoons fresh lemon juice
  • 3 cups all-purpose flour
  • 2 teaspoons baking powder
  • ½ teaspoon baking soda
  • ¼ teaspoon salt
  • 1 cup buttermilk room temperature
  • 2 cups blueberries fresh or frozen, plus more for the top of the cake
Mascarpone Lemon Frosting
  • 2 ½ cups heavy whipping cream cold
  • 1 ½ cups powdered sugar
  • 1 teaspoon lemon zest
  • 16 oz mascarpone cheese cold
Instructions
Lemon Custard
  1. Bring a small saucepan with 4 inches of water to a boil.
  2. Combine eggs, lemon zest, lemon juice and sugar in a heat-proof bowl. Place on top of the saucepan to create a double boiler. Make sure the water does not touch the bottom of the bowl.
  3. Whisk the lemon mixture for 3 minutes, stirring constantly to prevent clumping, until the mixture becomes well combined and light yellow.
  4. Add the butter and continue whisking and cooking for about 5 minutes, or until the mixture coats the back of the spoon.
  5. Transfer mixture to a bowl, cover tightly and refrigerate until cold. Can be made up to 4 days in advance.
Blueberry Lemon Cake
  1. Preheat oven to 350 degrees. Grease and flour three 8-inch or two 9-inch cake pans.
  2. In the bowl of your mixer, beat together butter, oil, and sugar until pale and fluffy (2-3 minutes). Scrape down the sides of the bowl and add eggs, one at a time, beating thoroughly before each addition. Stir in vanilla extract, lemon zest, and lemon juice.
  3. In a separate bowl, whisk together the remaining dry ingredients.
  4. Gradually alternate adding the dry mixture and the buttermilk to the butter/egg mixture (3 flour additions, 2 buttermilk additions), mixing only until just combined. After all the ingredients have been added, stir in the blueberries.
  5. Evenly spoon batter into prepared pans. Bake cakes for 25-27 minutes or until a toothpick is inserted in the center and comes out clean. Cool cakes in pans for 10 minutes then invert onto a cooling rack to cool completely.
Lemon Mascarpone Frosting
  1. Beat the heavy whipping cream, powdered sugar and lemon zest on high speed until soft peaks form.
  2. Add the cold mascarpone cheese whip the mixture until stiff peaks form. Refrigerate the frosting for about 10-15 minutes to firm up before using.
Assembly
  1. If necessary, cut off cake domes using a serrated knife to level.
  2. Place one layer of cake on a cake stand or serving plate.
  3. Pipe a border of frosting around the edge of the cake. Fill in the border with lemon custard. Top with the next layer and repeat.
  4. With remaining frosting, frost the outsides of the cake.
  5. Garnish with fresh blueberries, slice, and serve!