Lemon Layer Cake

Confession: This was the most involved cake that I've ever made...but so worth it. The planets must have been perfectly aligned because I even made lemon curd — something I've never done before — and it actually turned out! (I was afraid I'd scorch the sugar and it would taste like a burnt lemon cake)

The end result was amazing — the fluffy icing was the perfect compliment to the tart lemon filling.

Tip: To make things easier...the filling can be prepared two days ahead, and the cake can be made a day ahead of assembly — just cool the layers completely, wrap them tightly in plastic wrap and store in an airtight container in the refrigerator. Make the frosting just before putting the cake together.

Recipe adapted from America's Test Kitchen Family Baking Book


Makes 1 9-inch, 4-layer cake 

What You'll Need

For the cake:

2 1/4 cups cake flour, plus more for dusting the pans
1 cup whole milk, at room temperature
6 large egg whites, at room temperature
2 teaspoons pure vanilla extract
1 3/4 cups granulated sugar
4 teaspoons baking powder
1 teaspoon salt
12 tablespoons unsalted butter, cut into tablespoons, softened but still cool


For the filling:

Zest from two lemons
1 cup fresh lemon juice (from about 6 lemons)
1 teaspoon unflavored gelatin
1 1/2 cups granulated sugar
1/8 teaspoon salt
4 large eggs
6 large egg yolks (reserve whites for the cake)
8 tablespoons unsalted butter, cut into 1/2-inch cubes and frozen



What To Do

1. Begin by preparing the filling: Measure 1 tablespoon of the lemon juice into a small bowl and sprinkle the gelatin over the top to soften. With a mortar and pestle or with your fingertips in a small bowl, work the lemon zest into the sugar until the sugar is fragrant and evenly moistened with the oils from the zest.
2. Heat the rest of the lemon juice, the lemon sugar, and salt in a medium non-reactive saucepan over medium-high heat, stirring occasionally until the sugar is dissolved and the mixture is hot but not bubbling. Whisk the whole eggs and egg yolks in a large, non-reactive bowl. Slowly whisk the lemon syrup into the eggs, then return the mixture to the saucepan over medium-low heat. Cook the curd, stirring constantly, until it reaches 170 degrees and it's thick enough to draw a trail through it with a spatula. Stir in the softened gelatin until completely dissolved.
3. Remove the pan from the heat and stir in the frozen butter until the butter has melted and the curd is smooth. Pour through a fine mesh sieve into a non-reactive bowl. Cover the surface of the curd with plastic wrap and chill until firm, at least four hours or up to two days.

1. To make the cake, adjust an oven rack to the middle position and preheat the oven to 350 degrees. Grease and flour two 9-inch round cake pans and line the bottoms with parchment paper.
2. In a large measuring cup, whisk together the milk, egg whites and vanilla. In the bowl of a standing mixer fitted with the paddle attachment, mix together the flour, sugar, baking powder and salt at low speed. With the mixer running on low speed, add the butter pieces one at a time until the mixture resembles fine, even crumbs. Stop the mixer and add all but about 1/2 cup of the wet ingredients. Beat the batter at medium speed until it is pale and fluffy, about 1 1/2 minutes. With the mixer running on low, slowly pour in the rest of the wet ingredients, then crank the speed back up to medium and beat for 30 seconds more. Scrape down the bowl and beat for 30 more seconds.
3. Divide the batter equally among the two cake pans and smooth the tops. Bake for 23 to 25 minutes, or until a toothpick comes out clean--do not over bake. Let the cakes cool in the pans for 10 minutes, then remove the cakes from the pans, peel off the parchment and cool completely, right side up.
4. When the filling has chilled and the cake layers are cool, begin assembling the cake. Slice the cake layers in half horizontally. Place one layer golden side down on a serving platter, and tuck a few strips of parchment paper under the edges of the cake to protect the platter. Spread a third of the lemon filling on the cake layer, leaving a 1/2 inch border around the edge of the cake. Repeat twice more with cake layers and filling. Place the top layer of the cake golden side up. Frost with Fluffy White Icing. This cake is best served as soon as possible, but the finished cake can be covered with a cake dome and refrigerated up to one day before serving.
   

Seven year minute Frosting


2 large egg whites
1 cup granulated sugar
1/4 cup water
1 tablespoon fresh lemon juice
1 tablespoon light corn syrup
Pinch of salt

1. In the bowl of a standing mixer or another aluminum bowl, whisk together all of the ingredients. Place the bowl over a medium saucepan with about an inch of gently simmering water, making sure the water level doesn't touch the bottom of the bowl. Stir the mixture constantly and check the temperature often with an instant-read thermometer until it reaches 160 degrees.
2. Dry off the bottom of the bowl and place it on the mixer fitted with the whisk attachment (or set up an electric hand mixer). Whip the frosting on medium speed until it becomes opaque and soft peaks form, about five minutes. Turn the mixer up to medium-high and whip until the frosting is glossy, billowy and reaches a stiff peak and cools down to room temperature, about five minutes more. Use immediately and serve as soon as possible.