Preheat your oven to 350°F (175°C) and grease two muffin tins.

Whisk together flour, baking soda, and salt in a medium bowl.

Cream together unsalted butter and granulated sugar in a large bowl until light and fluffy.

Add eggs one at a time and mix in vanilla extract.

Gradually combine dry ingredients with the wet mixture until just incorporated.

Scoop dough into muffin tins and bake for 10-12 minutes until golden.

Press down centers to create wells and cool in pan for 5 minutes.

Heat milk and vanilla bean paste until simmering. Mix sugar, egg yolks, and cornstarch in another bowl.

Whisk hot milk into egg mixture, then return to heat and thicken for about 5-7 minutes.

Chill custard until cooled, then pipe into cookie cups and top with fresh berries.