Prepare your baking environment: line a baking sheet with parchment paper and chill another in the refrigerator for at least 15 minutes.

In a stand mixer, cream the room temperature butter on medium speed for about 3 minutes until smooth and creamy.

Gradually add granulated sugar and a pinch of salt, mixing until light and fluffy, about 4-5 minutes.

Add egg yolks, vanilla extract, and whole milk to the mixture and mix on low until fully incorporated.

In a separate bowl, whisk together the all-purpose flour and cake flour. Gradually add this flour mixture to the creamy batter.

Transfer the cookie dough into a piping bag fitted with a star tip and pipe 2-inch shapes onto the chilled baking sheets.

Chill the piped cookies in the refrigerator for 20-30 minutes to prevent spreading.

Preheat your oven to 350°F (175°C) while the cookies chill.

Bake the cookies for 10-15 minutes until golden around the edges. They should look set but soft.

Remove from the oven and cool on the baking sheet for about 5 minutes before transferring to a wire rack.