In a medium-sized mixing bowl, mix butter, cream cheese, and sugar until light and fluffy, about three minutes when using an electric mixer on high speed.
Mix in egg yolk and vanilla bean paste.
Whisk flour and salt together in a small bowl.
Add dry ingredients to wet ingredients a little bit at a time until just combined.
Using a cookie press, press cookies onto an ungreased cookie sheet.
Bake for 8-10 minutes or until lightly golden.
Cool on a cookie sheet for a few minutes. Then, transfer to cooling rack to cool completely.
It is best to use an ungreased cookie sheet when making cookie press cookies - that way the cookie dough sticks to the cookie sheet when you press it out of the cookie press. This is the one case where you want your dough to stick to the cookie sheet. After using the tool a bit on parchment paper, I quickly learned how frustrating it is when you lift the cookie press and the dough comes up with it instead of making a pretty pattern on the cookie sheet.The dough sticks even better if the cookie sheet is cold - try putting the cookie sheet in the freezer.This dough should come out of the cookie press nicely, but if you encounter any problems, just add a little milk at a time until it is soft enough to come through.You do not need to refrigerate the cookie dough, however if your house is warm and the dough becomes too soft to hold its shape, refrigerate for a few minutes.Spritz cookies can be stored at room temperature in an airtight container for a week. They also freeze really well! And, since they hold up so nicely, they are perfect for shipping to friends and family.