Lemon Curd Meringue Cupcakes

Ingredients:

Tartlets

• 6 tbsp (90 g) butter, room temperature
• 3 tablespoons of sugar
• A pinch of fine salt
• 1 large egg yolk
• 3/4 cup premium flour + extra for working with the dough
• 1 teaspoon sour cream or yogurt

Lemon filling

• 1/3 cup sugar
• 1 tbsp cornstarch
• 4 large egg yolks
• 2 tablespoons freshly squeezed lime juice (from about 1 lime)
• 1 tbsp finely grated lemon zest + 1/4 cup freshly squeezed lemon juice
• 3 tablespoons cold butter, diced
• 0.5 cups of sugar
• 1/4 cup egg whites (from about 2 large eggs)
• 1/4 tsp cream of tartar
• A pinch of fine salt
• Special equipment: round cookie cutter or 4-inch bowl, 6-cup non-stick muffin pan, 6 paper muffin cups, kitchen torch (optional)

Preparation:

1. In a medium bowl, beat the butter with a mixer on medium-high speed until smooth. Add the sugar and salt and continue beating. Scrape down the sides of the bowl, then fold in the egg yolk.
2. Add half the flour, beating until a crumbly dough forms. Scrape down the sides of the bowl again; add the remaining flour and sour cream, mixing until the dough is evenly moistened. Turn the dough out onto a lightly floured work surface and knead briefly.
3. Roll the dough between 2 generously floured sheets of waxed or parchment paper into a circle about 0.5 cm thick. Refrigerate for 1 hour.
4. Using an upside-down bowl or a large cookie cutter, cut out 6 circles with a diameter of 11 cm. Place the circles of dough into each cavity of a muffin tin and press them with your fingers or a glass to ensure the dough reaches all corners and up the sides of the tin. Freeze for 15-30 minutes.
5. Position a rack in the lower third of the oven and preheat the oven to 325°F (160°C). Spray the outsides of six paper muffin cups with cooking spray and place them in the cups containing the batter. Fill the cups with dried beans or pie weights.
6. Bake until the edges are golden brown, 25-30 minutes. Cool for 1 minute, then carefully remove the paper liners and weights. Return the pan to the oven and continue baking until set, another 15-20 minutes. Let cool slightly, then carefully remove the tartlets and cool completely on a wire rack.

7. Lemon filling

   
   In a non-reactive saucepan, combine the sugar, cornstarch, and egg yolks. Heat over medium-low heat, whisking constantly, until the mixture is smooth and the sugar is completely dissolved, about 1 minute. Add the lime juice, lemon zest, and lemon juice and continue heating, whisking constantly, until the mixture thickens like sour cream and begins to simmer, 3-4 minutes. Be sure to scrape down the sides of the saucepan to ensure even thickening.
   
   Strain the lemon curd through a fine sieve into a bowl. Gradually whisk in the butter until smooth. Stir until the curd cools. To cool faster, place the pan in a bowl of ice. Fill each tartlet with 1.5 tablespoons of the cooled lemon filling.

8. Meringue

   
   Pour a few centimeters of water into a saucepan large enough to accommodate the mixer bowl and bring to a boil. Whisk the sugar, egg whites, cream of tartar, and salt in the bowl of a stand mixer by hand. Place the bowl over simmering water and heat, whisking, until the mixture is hot to the touch (130°F) and the sugar is completely dissolved, 1-2 minutes. Transfer the bowl to a stand mixer fitted with the whisk attachment and beat the whites on medium-high speed until soft peaks form. Increase the mixer speed to high and continue beating until a stiff, cool meringue forms, about 10 minutes. Pipe the meringue from a pastry bag or spoon it over the filling.
   
   Just before serving, toast the meringue with a blowtorch. Alternatively, preheat the oven to high broil. Arrange the cakes on a baking sheet and broil under the broiler until the meringue is evenly browned, about 2 minutes. Serve immediately or refrigerate until ready to serve.
   
   Note:
   
   These cakes can be refrigerated for up to 2 days, or they'll keep well in the freezer for up to 1 week! Defrost 20 minutes before toasting and serving.
   
   Prepare in advance step by step:
   
   - Tartlets can be baked and frozen for up to 2 weeks.
   - Lemon curd can be stored in the refrigerator for up to 3 days.
   - The meringue can be whipped in advance and stored in the refrigerator for 1 day.