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 mix dry into wet until just combined; do not 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.

Cool on sheet 5 minutes, then rack. Serve warm with milk.