Clear space in your refrigerator and line baking sheets with parchment paper while you prepare the cookie dough.

In the bowl of a stand mixer, add room temperature European salted butter and beat it on medium speed until it's smooth and creamy, about 2 minutes.

Gradually sprinkle in granulated sugar and a pinch of salt, mixing until the mixture turns light and fluffy—this process should take another 2-3 minutes.

Add two egg yolks, vanilla extract, and whole milk to the creamed butter mixture and beat on low speed just until well combined.

In a separate bowl, whisk together all-purpose flour and cake flour until evenly blended. Gradually incorporate into the wet ingredients while mixing on low speed.

Transfer the dough to a piping bag fitted with a star tip. Carefully pipe desired shapes onto the prepared baking sheets.

Preheat your oven to 350°F (175°C). Once the cookies are nicely chilled, place them in the oven for 10-15 minutes.

Allow them to cool slightly on the sheets before transferring to a wire rack.