1. Combine butter, sugar, and vanilla extract with a hand mixer or Kitchenaid.
2. Add 1 egg and mix.
3. In a separate bowl mix flour, baking soda, cream of tarter, and salt.
4. Slowly add dry ingredients to wet ingredients. Mix until combined.
5. Form into a ball, wrap in plastic wrap, chill for at least 30 minutes.
6. Preheat oven to 350 degrees. Roll dough out to 1 inch thick. Cut with your favorite cookie cutters.
7. Bake on parchment paper for 7-8 minutes until puffy - do not let the cookies get brown!
8. Top with frosting and sprinkles.