In a medium saucepan, heat 2 cups of whole milk over medium heat until steaming but not boiling.

Whisk together 4 egg yolks, 1/2 cup granulated sugar, a pinch of salt, 1 teaspoon vanilla bean paste, and 2 tablespoons cornstarch in a bowl until smooth.

Gradually pour the hot milk into the egg mixture, whisking continuously.

Return this mixture to the saucepan and cook on medium-low heat for 8-12 minutes, stirring constantly until it thickens.

Remove from heat, stir in 2 tablespoons of unsalted butter, cover with plastic wrap directly on the surface, and refrigerate until cold.

Preheat your oven to 350°F (175°C).

In a small bowl, whisk together 2 cups all-purpose flour, 1 teaspoon baking powder, and 1/4 teaspoon salt.

In a large mixing bowl, cream 1/2 cup unsalted butter and 1 cup granulated sugar using an electric mixer on medium speed until light and fluffy, about 3-4 minutes.

Add in 1 egg and 1 teaspoon vanilla bean paste, mixing until well combined.

Gradually incorporate the dry ingredients until a soft dough forms.

Using a cookie scoop or a spoon, portion out the dough, rolling each piece into a ball.

Roll the balls in a bowl filled with additional granulated sugar.

Arrange the sugar-coated dough balls on parchment-lined baking sheets, leaving space between each.

Flatten each ball slightly with the palm of your hand.

Bake the cookies for 9-10 minutes or until the edges are lightly golden.

Allow them to cool on the sheets for about 5 minutes before transferring them to a wire rack.

Once the cookies are completely cool, pipe the chilled pastry cream generously onto the center of each cookie.

After piping, sprinkle a thin layer of granulated sugar on top of the pastry cream.

Using a kitchen torch, carefully caramelize the sugar until it melts and forms a golden, crispy coating.

Let the cookies cool for another 10 minutes before serving.