Preheat oven to 375°F (190°C). Line baking sheets with parchment paper.

Cream butter and 1 1/2 cups sugar in a large bowl until light and fluffy, about 3-4 minutes.

Beat in eggs one at a time, mixing well after each addition.

In a separate bowl, whisk together flour, cream of tartar, baking soda, and salt.

Gradually add dry ingredients to wet ingredients, mixing until just combined.

In a small bowl, mix 3 tbsp sugar and cinnamon for coating.

Shape dough into 1-inch balls, then roll in cinnamon sugar mixture to coat.

Place dough balls 2 inches apart on baking sheets. Bake for 8-10 minutes until edges are set but centers are still soft.

Let cookies cool on baking sheets for 5 minutes before transferring to wire racks.