Preheat your oven to 350°F (175°C) and spray a standard muffin tin with cooking spray.

In a medium bowl, whisk together the flour, baking soda, and salt until well combined.

In a large mixing bowl, beat the softened butter and granulated sugar until pale and fluffy.

Add the egg and vanilla extract, mixing until smooth.

Gradually mix the flour mixture into the butter mixture until just combined.

Fill each muffin cup halfway with the dough and bake for 10-12 minutes or until lightly golden.

Heat milk and vanilla bean paste in a saucepan until simmering. In a bowl, whisk together the remaining milk, egg yolks, sugar, and cornstarch.

Gradually mix the hot milk into the egg mixture, then return to heat until thickened.

Strain the custard through a sieve and cool in the refrigerator for 30 minutes.

Pipe the custard into the cooled cookie cups, topping with fresh berries and powdered sugar before serving.

Store leftovers in the refrigerator for up to 2 days.