Brown Butter Chocolate Chip Cookies

Melt the butter in a light-colored saucepan over medium heat. It will foam and sputter as the water cooks off, then quiet down. Swirl constantly for 5–8 minutes total until the milk solids at the bottom turn a toasty brown and it smells nutty. Immediately pour into a large heatproof bowl, scraping in all the brown bits. Stir in the water and let cool 20–30 minutes until warm but no longer hot (about 100°F / 38°C).

Add both sugars to the cooled brown butter and whisk 1 minute. Add the egg, yolk, and vanilla and whisk vigorously for about 1 minute more until thick, glossy, and lighter in color.

Whisk the flour, baking soda, and salt in a separate bowl, add to the wet mixture, and fold with a spatula just until a few streaks of flour remain. Add the chocolate and fold until no dry flour is visible. Cover and refrigerate at least 1 hour (up to 72 hours for deeper flavor) so the flour hydrates and the cookies spread less.

Heat the oven to 350°F (175°C) and line two sheet pans with parchment. Scoop 50 g balls (about 3 tbsp), spacing them 7 cm apart — about 8 per pan, for roughly 22 cookies. Bake one pan at a time on the middle rack 10–12 minutes, until the edges are golden brown and set but the centers look puffy and slightly underbaked. Sprinkle with flaky salt as soon as they come out. Cool 10 minutes on the pan to finish setting, then transfer to a rack.