In a standing 5-quart mixer with the paddle attachment, begin to cream together the butter and the sugar. Paddle on medium-high speed until light and fluffy, about 5 minutes.
Sift together the flour, salt, baking powder, and baking soda. Set aside.
Add in the eggs one at a time and vanilla and paddle until incorporated. Scrape down the sides of the bowl with a rubber spatula. Paddle until eggs and vanilla are incorporated, next add the sour cream. Paddle for 1 minute more on medium speed and be sure to scrape down the sides of the bowl again.
Pour in the dry ingredients on low speed and paddle until the dough comes together. This cookie dough is very sticky. Refrigerate at least for 4 hours or overnight.
On a heavily floured surface, begin to roll out your dough. Be sure to flour the top of the dough and the rolling pin. Roll to ¼ inch thick and cut in your favorite shapes. Place cookies on sheet trays lined with parchment paper or silpats. Bake at 350 degrees F./177 degrees C. for 10-12 minutes. Cookies should poof a bit and have a cake like consistency.
Cool and decorate as desired.