Pre-heat oven to 350 degrees.
If you have a stand mixer-fit with paddle beater. Beat on high speed the butter and until light and fluffy.
Add in sugar. Beat until the mixture is light and fluffy, about 2 minutes.
Scrape down the sides and turn your mixer to low. Add in the egg, sour cream, and vanilla and mix to combine.
Scrape down the sides. As the mixer is running on low speed add in the baking soda. Slowly add the flour a 1/2 cup at a time and mix to combine. Final dough will be soft.
Chill dough for at least 1 hour or overnight.
When you're ready to bake your cookies, lightly flour your work surface and rolling pin.
Roll dough to 1/4 inch thick. Cut shapes as desired.
Bake cookies on greased or parchment lined cookie sheets for 8-10 minutes.
Allow to cool completely and frost as desired