Make the Cupcakes:

1. Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners.
2. In a medium bowl, whisk together flour, baking powder, and salt. Set aside.
3. In a large bowl, beat butter and sugar together until light and fluffy.
4. Add eggs one at a time, beating well after each addition. Stir in vanilla extract.
5. Add the dry ingredients in two batches, alternating with the milk, and mix until just combined.
6. Divide batter evenly among cupcake liners, filling each about ⅔ full.
7. Bake for 18–20 minutes, or until a toothpick inserted in the center comes out clean.
8. Let cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Make the Pastry Cream Filling:

9. In a saucepan, heat milk over medium heat until warm (but not boiling).
10. In a separate bowl, whisk sugar, egg yolks, and cornstarch until smooth.
11. Slowly pour warm milk into the egg mixture, whisking constantly.
12. Pour the mixture back into the saucepan and cook over low heat, stirring constantly, until thickened (about 2–3 minutes).
13. Remove from heat, stir in vanilla and butter, then transfer to a bowl and cover with plastic wrap (pressing it onto the surface to prevent a skin from forming). Refrigerate until cool.

Assemble the Cupcakes:

14. Once cupcakes and pastry cream are fully cooled, use a small knife or cupcake corer to remove the center of each cupcake.
15. Spoon or pipe pastry cream into the hollowed-out centers.

Brûlée the Tops:

16. Sprinkle about ½ teaspoon of sugar evenly over the top of each cupcake.
17. Using a kitchen torch, caramelize the sugar until it turns golden brown and crisp. Let the sugar harden before serving.