Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, cream together the softened butter and 1 ½ cups granulated sugar until light and fluffy (about 3-4 minutes with a hand mixer).
Add the eggs one at a time, beating well after each addition.
In another bowl, whisk together the flour, cream of tartar, baking soda, salt, and nutmeg. Gradually add this dry mixture to the wet ingredients, mixing until just combined.
In a small bowl, combine the ground cinnamon and 2 tablespoons of granulated sugar for the coating.
Scoop out tablespoon-sized balls of dough and roll them into smooth balls.
Roll each ball in the cinnamon-sugar mixture until evenly coated.
Place the coated dough balls on the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 10-12 minutes, or until the edges are just golden and the centers look slightly underbaked. They will continue to firm up as they cool.
Remove from the oven and let the cookies sit on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.
Notes
Stack a few cookies on a decorative plate and dust with a light sprinkle of cinnamon sugar for an inviting display.