Add the flour and salt to a medium bowl and mix. Set aside.
Add the softened butter and sugar to a mixing bowl and cream them until light and fluffy.
Add the egg yolks and mix thoroughly scraping the sides of the bowl as needed.
Add the vanilla extract and combine.
Add the flour mixture to the batter a third at a time, mixing thoroughly in between.
Mix until just combined and there are no more flour streaks.
Preheat the oven to 350 degrees.
Add a small amount of the dough to a piping bag fitted with a large star tip. The dough should be thick, but pipeable. I double bagged my piping bag to try and avoid a blowout.
If it’s too thick, add it back to the dough and add a Tablespoon of milk and mix again. Try to pipe it again.
Once the dough is pipeable, pipe 1 ½ to 2-inch swirls on a parchment lined baking pan approximately 2 inches apart.
Bake for 10-12 minutes or until the edges are JUST starting to turn golden brown.
Remove them from the oven and allow to cool for 5 minutes before moving them to a cooling rack.
Optional: Once cool, add chocolate melting wafers to a microwave safe bowl and microwave 15 seconds at a time, stirring in between, until the chocolate is melted and smooth.
Dip the cookies into the chocolate and allow the extra to drip off.
Add a little pinch of sprinkles to the chocolate and set them on a wire rack to dry. Use a knife to gently release the dried cookies from the rack.