Lemon Layer Cake with Lemon Curd Filling and Vanilla Bean 7 Minute Frosting

I am so in love with this lemon cake.  I don't do lemon desserts too terribly often, which is odd because lemon is amazing!  Looking back over the not very many lemon recipes we've posted, I really want to make some of them again!  Like the Lemon Meringue Ice Cream Pie, Lemon White Chocolate Coconut Macadamia Cookies, Bread and Butterflies Lemon Pound Cake, and Lemon Poppyseed Cake with Vanilla Bean Cream Cheese Frosting.  Yum.  This cake starts with three layers of lemon cake and is filled with a luscious lemon curd.  The whole thing is topped off with a light and fluffy Vanilla Bean 7 minute frosting.  Delicious!  Note:  Assemble the cake before you make the frosting or the frosting may set up too much and you won't be able to spread it.

Lemon Layer Cake with Lemon Curd Filling and 7 Minute Frosting

Lemon Curd:
3/4 cup granulated sugar
1/4 cup cornstarch
1/4 cup water
1/2 cup fresh lemon juice
2 eggs
1 Tablespoon fresh lemon zest
1/4 cup (1/2 stick) butter, room temperature

Lemon Cake:
1 cup (2 sticks) butter, room temperature
2 cups granulated sugar
3 eggs
1 teaspoon vanilla extract
Zest of 1 lemon
3 1/2 cups all purpose flour
2 teaspoons baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
1 3/4 cups sour cream
1/4 cup fresh lemon juice 

Vanilla Bean 7 Minute Frosting:
2 egg whites
1 1/2 cups granulated sugar
1/4 cup cold water
1 Tablespoon light corn syrup
1 teaspoon vanilla extract
Seeds of one vanilla bean

For the lemon curd, whisk together the sugar and cornstarch in a medium saucepan.  Add the water and whisk until smooth.  Whisk in the lemon juice and eggs, and cook over medium heat, stirring constantly, until the mixture is thick and bubbly.  Remove the saucepan from the heat and whisk in the butter and lemon zest until the butter is melted and completely incorporated.  Transfer the lemon curd to a bowl, cover with plastic wrap, and chill until completely cold.

For the lemon cake, preheat the oven to 350F.  Grease 3 9-inch round cake pans and line the bottoms with parchment paper, then lightly grease the parchment paper.

In a large bowl, or the bowl of a stand mixer, cream together the butter and sugar until light and fluffy.  Beat in the eggs, one at a time, then beat in the vanilla and lemon zest.  Combine the flour, baking powder, baking soda, and salt in a small bowl.  Add 1/3 of the flour mixture to the creamed mixture and beat on low until it starts to blend.  Add half of the sour cream and lemon juice, and beat on low.  Add another 1/3 of the flour mixture, followed by the remaining sour cream and lemon juice.  On low speed, beat in the remaining flour mixture until just combined, scraping the sides as needed.  

Divide the batter evenly among the three prepared pans and smooth the tops. Bake the cakes for about 25 minutes, or until a toothpick inserted in the center comes out clean and the edges are just slightly browned.  Remove cakes from the oven and let cool for about five minutes.  Run a knife around the edge of the pans, then carefully turn the cakes out of the pans.  Remove the parchment paper from the bottom of the cakes (if necessary), and let cool completely on a cooling rack.

When you are ready to assemble the cake, remove the lemon curd from the fridge and stir to loosen it up so it is spreadable.  Place one cake layer on a serving plate and spread half of the lemon curd over the top.  Top with a second cake layer and spread the remaining lemon curd over the top.  Place the third cake layer on top and set aside while you make the frosting.

For the vanilla bean 7 minute frosting, in a large metal bowl over a saucepan of simmering water, place the egg whites, sugar, water, and corn syrup.  With an electric mixer, beat the mixture for 3 minutes on low speed.  Increase the speed to high and continue to beat for another 3 minutes, until the frosting is shiny with soft peaks.  Remove the bowl from over the simmering water and add the vanilla and vanilla bean seeds.  Beat for 1 to 2 minutes or until the frosting is thick and stiff peaks form.

Immediately spread the frosting over the top and sides of the cake.  Makes about 16 servings.

Enjoy!  -Cardamommy