A snickerdoodle is usually a plain cookie carried entirely by its cinnamon crust. Browning the butter changes that. What comes out has a nutty, almost caramel depth underneath, and the cinnamon becomes the top note rather than the whole song.

The cream of tartar stays, and it should. It is what makes a snickerdoodle taste faintly tangy instead of just sweet — the thing that separates it from a cinnamon sugar cookie. Without it you have made something else.

Ingredients

The dough

1 cup (2 sticks) unsalted butter
1½ cups granulated sugar
2 large eggs
1 large egg yolk
1 tsp pure vanilla extract
2¾ cups all-purpose flour
2 tsp cream of tartar
1 tsp baking soda
½ tsp fine sea salt

The rolling sugar

¼ cup granulated sugar
1 tbsp ground cinnamon

Method

Melt the butter in a light-colored saucepan over medium heat, swirling often, until the milk solids are deep golden and smell nutty, 5–7 minutes. Pour it into a mixing bowl, scraping in every browned bit, and let it cool 15–20 minutes.
Whisk the sugar into the cooled brown butter until smooth. Add the eggs, the extra yolk, and the vanilla, and whisk until glossy.
Stir in the flour, cream of tartar, baking soda, and salt just until no dry streaks remain. Do not overmix.
Cover and refrigerate at least 45 minutes. This deepens the flavor and keeps the cookies from spreading thin.
Heat the oven to 350°F and line baking sheets with parchment. Stir the rolling sugar and cinnamon together in a shallow bowl. Scoop the dough into roughly 1½-tablespoon balls, roll each generously in the cinnamon sugar, and set them two inches apart.
Bake 9–11 minutes, until the edges are set and lightly golden while the centers still look slightly soft. Do not wait for the centers to look done.
Rest on the baking sheet 5 minutes, then move to a wire rack.

To freeze: chill the dough first, then scoop and roll in cinnamon sugar. Freeze on a tray until solid and transfer to a bag. Bake straight from frozen at 350°F for 10–13 minutes, pulling them while the centers still look underdone.