Preheat your oven to 375°F and line baking sheets with parchment paper.
In a large mixing bowl, cream together the butter and 1½ cups sugar until light and fluffy, about 3-4 minutes.
Beat in the eggs one at a time, then add the vanilla extract and mix well.
In a separate bowl, whisk together the flour, cream of tartar, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Don't overmix!
In a small bowl, combine the ¼ cup sugar and cinnamon for rolling.
Roll the dough into 1½-inch balls, then roll each ball in the cinnamon-sugar mixture until completely coated.
Place the cookies 2 inches apart on the prepared baking sheets.
Bake for 10-12 minutes, until the edges are set but the centers still look slightly underdone. They'll continue to cook on the pan.
Let cool on the baking sheet for 5 minutes before transferring to a wire rack. Enjoy them warm with a cold glass of milk!