Make the Lemon Cupcakes:

1. Preheat the oven to 350°F (175°C) and line a cupcake pan with liners.
2. In a bowl, whisk together flour, baking powder, and salt. Set aside.
3. In a large bowl, beat butter and sugar until light and fluffy.
4. Add eggs, one at a time, mixing well. Stir in vanilla extract, lemon zest, and lemon juice.
5. Alternately add the dry ingredients and milk, mixing until just combined.
6. Divide the batter evenly into the cupcake liners.
7. Bake for 18–20 minutes, or until a toothpick inserted comes out clean.
8. Let cupcakes cool completely before filling.

Make the Lemon Curd Filling:

1. In a small saucepan over medium heat, whisk egg yolks, sugar, lemon juice, and lemon zest.
2. Stir constantly for 5–7 minutes until the mixture thickens.
3. Remove from heat and stir in butter until smooth.
4. Let cool before using.

Fill the Cupcakes:

1. Use a small knife or cupcake corer to remove the center of each cupcake.
2. Fill each hole with a spoonful of lemon curd.

Make the Meringue Topping:

1. In a heatproof bowl over a double boiler, whisk together egg whites, sugar, and cream of tartar.
2. Heat and whisk constantly until the sugar dissolves (about 3 minutes).
3. Remove from heat and beat with a hand mixer until stiff peaks form. Stir in vanilla extract.
4. Pipe or spread the meringue onto the cupcakes.

Toast & Serve:

1. Use a kitchen torch to lightly toast the meringue, or place the cupcakes under the broiler for 1–2 minutes (watch closely!).
2. Serve and enjoy these light, citrusy, and delicious Lemon Meringue Cupcakes!