Add the butter to a saucepan and heat on medium-high heat. Allow the butter to melt and then stir continuously until the butter begins to brown in color and smells nutty. Remove from heat and cool the butter in the refrigerator until the butter is solidified, but still soft. 

In medium bowl, mix together the flour, cream of tartar, baking soda, salt, and cinnamon. Set aside.

Add the butter and sugar to a mixing bowl and beat until light and fluffy. Add in the eggs and beat well for about 2 minutes.

Gently add in the flour mixture to the butter mixture and fold in until there are no streaks of flour.

Chill the cookie dough for at least an hour.

Mix together the sugar and cinnamon for the coating. Preheat the oven to 350 degrees F. Line two baking sheets with parchment paper or a silicone baking mat.

Make balls of cookie dough using two tablespoons of dough per ball. Roll each ball in the cinnamon sugar and place on your baking sheets at least two inches apart.

Bake for 10 - 12 minutes, or until a light golden brown.

Remove the cookies from the oven and allow to cool on a wire rack. Store in an airtight container for up to a week.