Preheat oven to 350F.
In a bowl, cream together butter and cream cheese. Add sugar, beat to incorporate. Add egg yolk and beat until light and fluffy. Add vanilla and beat to combine.
In a separate bowl combine flour and salt. Add flour gradually to the butter mixture and beat until incorporated.
Place the dough (you'll need to work in batches) in the cookie press with the desired disk. Press dough out onto clean, ungreased cookie sheet. (Do not cover the baking sheet with parchment, wax paper or aluminum foil)!
Sprinkle cookies with holiday sprinkles (optional).
Bake for 13-15 minutes, until golden brown on the edges, rotating the sheets once halfway through (be careful not to burn them!).
Remove from the oven and let cookies cool for 5-7 minutes, then transfer to a cooling rack or a platter.