Preheat your oven to 350°F (175°C) and line your cookie sheets with parchment paper.

In a large mixing bowl, beat the softened unsalted butter and granulated sugar together until light and fluffy, about 2-3 minutes.

Add the egg yolks and vanilla extract to the mixture and mix until well blended.

Sift in the all-purpose flour and salt, mixing on low speed until large crumbles form.

Pour in the milk slowly and mix until the dough achieves a sticky and thick consistency.

Fit a piping bag with a large star tip, fill it with cookie dough, and pipe the dough onto prepared cookie sheets.

Chill the piped cookies for about 15-30 minutes if your kitchen is warm, then bake for 13-15 minutes.