Lemon Curd Layer Cake
1 cup (2 sticks) unsalted butter, plus more for the pan
3 cups cake flour, not self-rising
2 1/2 teaspoons baking powder
1 teaspoon salt
2 cups granulated sugar
4 large eggs, room temperature
1 cup whole milk, room temperature
1 teaspoon pure vanilla extract
Lemon Curd Filling
1 cup granulated sugar
3 tablespoons cornstarch
1 cup water
5 large egg yolks, room temperature
1/2 cup freshly squeezed lemon juice
Small pinch of salt
Zest of 2 lemons
4 tablespoons ( 1/2 stick) unsalted butter, diced and chilled, plus more for the plastic wrap
1 1/2 cups granulated sugar
1/3 cup warm water
2 large egg whites, room temperature
1 tablespoon light corn syrup
Pinch of fine salt
1 teaspoon pure vanilla extract
Organic edible flowers such as violets, Johnny-jump-ups or nasturtiums (optional)
Heat oven to 350 degrees. Arrange two racks in center of oven. Butter three 9-inch round cake pans; line bottoms with parchment paper. Dust bottoms and sides of pans with flour; tap out any excess. Remove from heat and whisk in the lemon zest and butter, a little at a time. To prevent a skin from forming, press a piece of buttered plastic wrap onto the surface. Cool, then cover and refrigerate until use.
In a large bowl, sift together the flour, baking powder and salt; set aside.
In the bowl of an electric mixer fitted with the paddle attachment, cream the butter on medium speed until softened, 1 to 2 minutes. Gradually add the sugar, beating on medium speed until lightened, 3 to 4 minutes; scrape down sides once or twice. Add eggs, one at a time, beating after each addition.
On low speed, alternately add flour mixture and milk, a little of each at a time, beginning and ending with flour mixture. Beat in the vanilla.
Divide the batter evenly among the prepared pans. Bake until a cake tester inserted into the center of each cake comes out clean, 25 to 30 minutes. Transfer the pans to a wire rack to cool slightly, about 5 minutes. Turn out cakes; set on racks, tops up, until completely cool.
To make the lemon curd: While the cakes are cooling, make the filling. Whisk together sugar, cornstarch, water, yolks, lemon juice and salt in a medium-size heavy saucepan. Cook over medium heat, whisking constantly, until the mixture is thickened, 4 to 5 minutes.
Remove the parchment from bottom of each cake. Using a serrated knife, slice each layer in half horizontally. Set aside the prettiest domed layer for the top of the cake. Place another domed layer, dome side down, on a cake platter.
Spread about 1/2 cup of lemon curd over surface to within 1/2 inch of edge. Place second cake layer over the first and spread 1/2 cup of lemon curd on top. Repeat with remaining curd and layers, including lemon curd on the top of the cake. Transfer the partially assembled cake to the refrigerator to set, at least 30 minutes.
To make the frosting: Combine the sugar, water, egg whites, corn syrup and salt in the heatproof bowl of an electric mixer. Place the bowl over a bowl of simmering water and cook over medium heat, stirring frequently, until the sugar is dissolved and the mixture is very warm to the touch or registers 160 degrees on an instant-read thermometer, 2 to 4 minutes.
Attach bowl to a mixer fitted with the whisk attachment. Beat mixture on high speed until glossy and voluminous, about 5 minutes. Beat in vanilla. Use immediately.
Place some of the frosting in a piping bag fitted with a round tip. Pipe around the edges of the top layer of the cake to create a dam around the lemon curd. Using an offset spatula, frost the sides of the cake with the remainder of the frosting. Garnish around the bottom and on top of the cake with edible flowers. Serve.
Cupcake variation: Preheat oven to 375 degrees. Line regular-size muffin tins with 27 paper cups (fill empty cups partially with water). Follow the cake recipe preparation; pour batter into the cups, filling each 3/4 full. Transfer to oven and bake until golden brown, about 20 minutes. Remove to a rack to cool.
Once cooled, place the frosting in a pastry bag fitted with a small round tip. Push the tip through the top of each cupcake; insert frosting. Using a small offset spatula, cover each top with a heaping tablespoon of lemon curd. Pipe small swirls of frosting around the edges of the curd-coated cupcakes. Place edible flowers at the center of half the cupcakes and place edible flowers around the edge of the remaining cupcakes.
Heat oven to 350 degrees. Arrange two racks in center of oven. Butter three 9-inch round cake pans; line bottoms with parchment paper. Dust bottoms and sides of pans with flour; tap out any excess.
Remove from heat and whisk in the lemon zest and butter, a little at a time. To prevent a skin from forming, press a piece of buttered plastic wrap onto the surface. Cool, then cover and refrigerate until use.
Per cupcake (includes filling and frosting): 619 calories (percent of calories from fat, 30), 37 grams protein, 72 grams carbohydrates, 2 grams fiber, 20 grams fat (3 grams saturated), 88 milligrams cholesterol, 459 milligrams sodium.