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

In a large mixing bowl, cream together 1 cup of softened unsalted butter and ⅔ cup of granulated sugar on medium speed until light and fluffy (about 3-5 minutes).

Add 2 egg yolks and 1 teaspoon of vanilla extract to the mixture and blend on low speed until fully incorporated (about 1-2 minutes).

Gradually sift in 2 cups of all-purpose flour and ¼ teaspoon of salt while mixing on low speed until large crumbles form.

Drizzle in 2 tablespoons of milk and mix until the dough is thoroughly absorbed (about 1 minute).

Transfer the dough into a piping bag fitted with a large star tip.

Pipe the dough onto the prepared baking tray into swirls, leaving enough space between each cookie.

Bake for about 13-15 minutes, or until the edges are lightly golden brown. Let cool slightly before transferring to a wire rack.