Preheat oven to 350 degrees. Line a baking sheet with parchment paper and set aside.
In a large mixing bowl, use a hand-held mixer to beat together the butter and sugar until light and fluffy.
Next, add the egg yolks and vanilla extract. Beat to combine.
Add the flour and salt and beat to combine. The dough will be crumbly. Add the milk, one teaspoon at a time until the dough comes together. Don't exceed 3 teaspoons of milk, otherwise, the cookies will spread too much.
Transfer the cookie dough to a large piping bag that has been fitted with a large star tip. Pipe the dough onto the prepared baking sheet in a rosette/circular fashion.
Top the cookies with sprinkles and bake for 15 minutes.
Remove cookies from the oven and cool on the baking sheet for 5 minutes before removing to a cooling rack to finish cooling.