From: https://www.modernhoney.com/the-best-snickerdoodle-cookie-recipe/

Ingredients:
- 1 cup Unsalted Butter (softened)
- 1 1/2 cups Sugar
- 2 large Eggs
- 2 teaspoons Vanilla
- 2 3/4 cup Flour
- 1 1/2 teaspoon Cream of Tartar (for less tang, use 1 teaspoon)
- 1/2 teaspoon Baking Soda
- 3/4 teaspoon Salt
cinnamon-sugar mixture:
- 1/4 cup sugar
- 1 1/2 tbsp cinnamon

Preparation:
1) Preheat oven to 350 degrees.
2) In a large mixing bowl, cream butter and sugar for 4-5 minutes until light and fluffy.  Scrape the sides of the bowl and add the eggs and vanilla. Cream for 1-2 minutes longer.
3) Stir in flour, cream of tartar, baking soda, and salt, just until combined.
4) In a small bowl, stir together sugar and cinnamon.
5) If time allows, wrap the dough and let refrigerate for 20-30 minutes.  Roll into small balls until round and smooth.  Drop into the cinnamon-sugar mixture and coat well. Using a spoon, coat for a second time, ensuring the cookie balls are completely covered.  *To make flatter snickerdoodles, press down in the center of the ball before placing in the oven. This helps to keep them from puffing up in the middle. *
6) Place on a parchment paper-lined baking sheet. Bake for 9-11 minutes.  Let cool for several minutes on baking sheet before removing from the pan.