Makes 24
Ingredients:
For the cupcakes:
1 cup milk
1/4 cup fresh squeezed lemon juice
3 cups all-purpose flour
1 tablespoon baking powder
1/2 teaspoon salt
1 cup (2 sticks) unsalted butter, room temperature
2 cups sugar
4 large eggs, room temperature
Finely grated zest of 3 lemons (about 3 tablespoons)
1 teaspoon pure vanilla extract or vanilla paste
For the curd:
2 large eggs, cold
2 large egg yolks, cold (learn the best way to separate eggs here)
3/4 cup sugar
1/2 cup fresh squeezed lemon juice
6 tablespoons (3 ounces) cold unsalted butter, cut into 6 pieces
For the meringue:
6 egg whites
12 ounces granulated sugar
Procedure:
Make the cupcakes:
Preheat oven to 325 degrees. Line standard muffin tins with paper liners.
Whisk together milk and lemon juice and allow to stand at room temperature. In another small bowl, whisk together flour, baking powder, and salt. Set aside.
With an electric mixer on medium speed, cream butter and sugar until pale and fluffy. Add eggs, one at a time, beating until each is until incorporated, scraping down sides of bowl as needed. Beat in zest and vanilla. Add flour mixture in three batches, alternating with two additions of milk mixture, and beating until just combined after each.
Divide batter evenly among lined cups, filling each three-quarters full. Bake, rotating tins halfway through, until golden brown and a cake tester inserted in centers comes out clean, about 25 minutes. Transfer tins to wire racks to cool completely before removing cupcakes.
Make the curd:
Bring about 1 1/2 inches of water to a boil in the base of a double boiler. Meanwhile, in the top of the double boiler, whisk the eggs, yolks, and sugar until the mixture is smooth, about 1 minute. Set the top of the double boiler over the water and whisk the mixture constantly for 2 minutes, or until eggs are foamy and have thickened.
Add one-third of the lemon juice. Continue to whisk vigorously and, when the mixture thickens again, add another one-third of the lemon juice. Whisk until the mixture thickens again and add the remaining lemon juice. Continue whisking vigorously until the mixture is thickened and light in color and the whisk leaves a trail in the bottom of the bowl. The total cooking time should be 8 to 10 minutes.
Turn off the heat, leaving the double boiler assembled. Whisk in the butter one piece at a time, whisking until butter is completely melted before adding the next piece. Chill until set.
Make the Swiss Meringue:
Bring about 1 1/2 inches of water to a boil in the base of a double boiler. Place bowl with egg whites and sugar on top of double boiler and whisk constantly until sugar is dissolved and egg whites are slightly warmed.
Transfer egg white mixture to the bowl of a stand mixer fitted with a whisk attachment. Whip on a high speed until stiff peaks form and meringue has cooled.
Assemble cupcakes:
Using a cupcake corer, apple corer, or paring knife, make a small hole in the center of each cupcake. Spoon or pipe curd into each hole (you may have extra curd). Pipe meringue on top of each cupcake. If desired, torch meringue lightly. Serve immediately.