Preheat oven to 350°F. Line two cookie sheets with parchment paper or Silpat baking mats.

In a stand mixer fitted with the paddle attachment (or with a hand mixer), cream 3/4 cup (170 g) unsalted butter and 3/4 cup (150 g) granulated sugar on medium speed until light and fluffy, about 2–3 minutes.

Add 1 large egg and 1 tablespoon vanilla extract; mix until smooth and fully incorporated.

Add 1/2 teaspoon baking soda, 1/2 teaspoon cream of tartar, and 1/2 teaspoon salt; mix briefly just to combine.

With the mixer on low, slowly add 2 cups (248 g) all-purpose flour and mix until the dough is just combined. Do not overmix.

If using, fold in 1 cup (170 g) chocolate chips with a spatula until evenly distributed.

In a small bowl, stir together 1/3 cup (67 g) granulated sugar and 2 teaspoons ground cinnamon to make the cinnamon-sugar coating.

Scoop dough into 2-tablespoon portions (use a 2-T scoop or two spoons), roll each portion into a ball, then roll the ball in the cinnamon-sugar to coat.

Place the coated dough balls 2 inches apart on the prepared cookie sheets.

Bake 9–11 minutes, until the bottoms just start to turn golden brown. For softer cookies, err on the side of the shorter baking time.

Cool the cookies on the baking sheet for at least 5 minutes before transferring to a rack or plate to finish cooling.

Store cooled cookies in an airtight container for up to 3 days, or freeze for up to 1 month.