In large stand mixer with the paddle attachment, cream together sugar, butter, and cream cheese until pale and fluffy, scraping down the bowl occasionally. Turn mixer off, remove the paddle and manually stir in the vanilla, eggs, salt, and flour until the flour is moistened (to prevent flour from being propelled from the mixer when you start it up again). Re-attach the paddle and bowl and mix on low speed until all flour has been thoroughly combined, approximately 30-45 seconds.
Scrape dough onto a plate or into a 8" x 8" pyrex dish and smooth the dough into a flat shape. Cover with plastic wrap and refrigerate for at least an hour or until firm.
Pre-heat oven to 375°F Lightly dust a counter or work bench with all-purpose flour. Remove a fist-sized quantity of dough from the dish and return un-used dough to the refrigerator. Quickly work the dough into a flat disk, lightly dust with flour, and roll to 1/8" thickness. Cut out shapes with cutters or free-hand with a paring knife. The excess dough around the shapes may be dusted of excess flour and returned to the refrigerated dough for later use.
Lay cut cookies onto an un-greased cookie sheet (preferably lined with parchment) and bake 10-15 minutes or until the tops are no longer shiny and the cookies are just browned around the edges. Allow to cool in the pan 2 minutes, then remove cookies from the pan and allow to finish cooling on a cooling rack. Cookies may be frosted when they are room temperature.