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

In a large mixing bowl, cream together the softened butter and granulated sugar on medium speed until light and fluffy, about 2-3 minutes.

Add the egg yolks and vanilla extract to the butter mixture and beat on low speed until fully incorporated, about 1-2 minutes.

Gradually mix in the all-purpose flour and salt until large crumbles form.

Stir in milk by the tablespoon until the dough is thick and slightly sticky.

Transfer the dough into a piping bag and pipe into rosettes or swirl shapes on the baking sheets, leaving about 2 inches between each cookie.

Chill the piped cookies in the refrigerator for about 30 minutes if the dough is too soft.

Bake for 13-15 minutes or until the edges are lightly golden brown. Let cool on the baking sheets for a few minutes before transferring to a wire rack.