Heat the whole milk in a saucepan over medium heat until steaming, but do not boil. In a bowl, whisk together egg yolks, granulated sugar, salt, vanilla bean paste, and cornstarch until combined. Gradually pour the warm milk into the mixture, stirring continuously. Return to heat and cook for 8-12 minutes, stirring until thickened. Stir in unsalted butter, let cool, and refrigerate.

Preheat your oven to 350°F (175°C). In a mixing bowl, whisk together all-purpose flour, baking powder, and salt. In a separate bowl, beat together unsalted butter and granulated sugar until light and fluffy. Add in the egg and vanilla extract, mixing well. Gradually mix in the dry ingredients until just combined.

Scoop the dough into uniform balls about 1 inch in diameter. Roll each ball in granulated sugar and gently flatten on a parchment-lined baking sheet, spacing them about 2 inches apart. Bake for 9-10 minutes until the edges are light golden brown but the centers remain soft. Allow to cool completely on a wire rack.

Pipe a generous amount of chilled pastry cream onto the center of each cookie. Smooth and evenly spread the cream.

Sprinkle superfine sugar evenly over the pastry cream on each cookie. Using a kitchen torch, caramelize the sugar until it melts and forms a golden-brown crust.

Serve your crème brûlée cookies fresh with the brûléed topping. Best enjoyed the same day for optimal chewy texture.