In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy (about 2-3 minutes).

Beat in the eggs one at a time, followed by the vanilla extract, until well combined.

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 until a soft dough forms.

Cover the dough and chill in the refrigerator for at least 30 minutes. Chilling helps the cookies keep their shape while baking.

In a small bowl, mix the granulated sugar, ground cinnamon, and sprinkles (if using). The sprinkles give the cookies a festive look, but they’re optional if you prefer a classic snickerdoodle.

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

Scoop about 1 ½ tablespoons of dough and roll it into a ball. Roll the ball in the cinnamon sugar mixture, coating it generously.

Place the coated dough balls on the prepared baking sheets, spacing them about 2 inches apart.

Bake the cookies for 8-10 minutes, or until the edges are set but the centers still look slightly underbaked. This ensures they stay soft and chewy. Remove the cookies from the oven and allow them to cool on the baking sheets for 2-3 minutes before transferring to a wire rack to cool completely.