Soft Brown Sugar Cookies

Heat the oven. Preheat to 350°F. Set a rack in the middle of the oven. Line a baking sheet with parchment paper. (For the most even bake, do one sheet at a time.)

Mix the wet ingredients. In a large bowl, whisk the melted butter and brown sugar until fully combined, glossy, and smooth, about 30 seconds. Whisk in the egg, egg yolk, and vanilla until the mixture looks a little lighter and thicker.

Add the dry ingredients. Add the flour, cornstarch (if using), baking soda, baking powder, salt, and cinnamon (if using). Switch to a spatula and fold just until no dry streaks remain. Do not overmix. Cookie dough can be a little particular.

Optional (extra-even mixing): If you prefer, whisk the dry ingredients together in a separate bowl first, then fold them into the wet ingredients.

The dough should look soft, slightly glossy, and scoopable.

Chill briefly. Chill the dough for 10 minutes, or longer if your kitchen is warm, until the dough feels cool and easy to scoop. This helps the cookies bake up thicker with better edges.

Scoop and (optional) roll. Scoop dough into 1 1/2-tablespoon portions (about 35 to 40 g each). Roll in granulated sugar if you want extra sparkle and crisp edges. Place on the baking sheet, leaving 2 inches between cookies.

Bake. Bake for 9 to 11 minutes, until the edges look set and lightly browned and the centers look puffed, crackly, and still a bit soft. They will finish setting as they cool. That slightly underdone center is your chewy future.

Cool and finish. Let cookies cool on the pan for 5 minutes, then transfer to a wire rack. If you want, add a tiny pinch of flaky salt while they are still warm.