Preheat your oven to 350°F (175°C) and line a muffin tin with cupcake liners.

In a bowl, cream together the softened butter and sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition. Then stir in the vanilla extract.

In a separate bowl, whisk together the flour, baking powder, and salt.

Gradually combine the dry ingredients with the creamed mixture, alternating with the milk. Mix until just combined.

Divide the batter evenly among the cupcake liners, filling each about two-thirds full.

Bake for 18–20 minutes, or until a toothpick inserted into the center comes out clean.

Let the cupcakes cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.

In a saucepan over medium heat, combine the milk, sugar, and cornstarch. Stir constantly until the mixture thickens and comes to a gentle boil.

Remove from heat. In a separate bowl, whisk together the egg yolks. Slowly add a cup of the hot milk mixture to the yolks, whisking constantly to temper the yolks.

Pour the yolk mixture back into the saucepan with the rest of the milk mixture. Cook for another minute, then remove from heat and stir in the vanilla extract.

In a medium saucepan, heat the heavy cream until just boiling. Remove from heat and add the chocolate chips.

Allow it to sit for a couple of minutes, then stir until smooth and glossy.

Once the cupcakes are cool, cut a small hole in the center of each cupcake and fill it with the vanilla custard.

Top each filled cupcake with a generous drizzle of chocolate ganache.

Let the ganache set for a few minutes before serving.