Cream butter and sugar together in a stand mixer. Then add eggs and vanilla, mixing until incorporated. Add sour cream.
Combine salt, baking soda and flour. Then add to mixture a bit at a time (this helps it mix as well as keeps flour from flying everywhere).
Place in plastic wrap and refrigerate for 30 min or until ready to use.
When ready to bake, preheat oven to 350°.
Roll out dough, not too thin though, try to get it about 1/4 of an inch or so. Cut out your angels, stars, bells, trees, snowflakes, snowmen, gingerbread men, etc...
Place on baking sheet with a silpat or parchment paper and bake for 7-8 minutes. You do not want to bake for much longer or they will lose their fluffiness.
You can cut this batch in half and it will work just fine. I have done that many times. I often will make all the dough and bake half or so of it and save the rest for the next week.
You can take the dough after it is cut and re-roll it, but only 2-3 times before the texture starts to change.