Brown Butter Chocolate Chip Cookies

Brown the butter: Melt the butter in a medium saucepan over medium heat, stirring constantly with a rubber spatula. Keep going past the foam, scraping the bottom often, until the milk solids turn deep amber and the butter smells nutty and toffee-like — about 5-8 minutes. Pour into a heatproof measuring cup, scraping every browned speck out of the pan. Do not top up with extra butter — the final volume will be a touch under 1 cup, which is the point. Refrigerate uncovered until cooled to room temperature and just starting to set around the edges, about 45 minutes.

Whisk dry ingredients: In a medium bowl, whisk together the King Arthur AP flour, King Arthur cake flour, kosher salt, baking soda, and baking powder until evenly combined. Set aside.

Mix butter and sugars: Pour the cooled brown butter (including every dark fleck) into a large bowl. Add the dark brown sugar and granulated sugar and whisk vigorously until fully combined and the mixture looks like wet sand, about 1 minute.

Add eggs and aromatics: Add the vanilla, lemon juice, whole egg, and egg yolk. Whisk vigorously for about 2 minutes — the mixture should turn a shade lighter and feel slightly thicker. The lemon juice brightens the brown butter and helps the emulsion hold.

Fold in flour: Add the dry ingredients to the bowl. Fold with a rubber spatula until just a few dry streaks remain — do not fully combine yet.

Add chocolate: Add the chopped dark chocolate chunks and the finely chopped milk chocolate. Fold gently until just incorporated and no dry flour remains. Stop the moment it comes together — overmixing toughens the crumb.

Portion and chill: Using a 2 oz cookie scoop (about 70-75g each), portion 14 dough balls onto a parchment-lined plate or sheet pan. Cover loosely and refrigerate for at least 4 hours, ideally overnight, for best flavor, color, and ripple structure.

Preheat: When ready to bake, preheat the oven to 350°F with conventional heat. Line a baking sheet with parchment paper — not a silicone mat, which holds heat and over-spreads these cookies.

Bake: Place 3-4 chilled dough balls on the sheet, spaced at least 2 inches apart. Bake for 12-14 minutes, until the edges are set and golden brown and the centers still look slightly soft and underdone. They will continue to set on the pan.

Shape and salt: The moment they come out of the oven, use a fork or the rim of a round cutter to gently nudge any wonky edges into circles — this is also when you get the ripply ring on top by swirling lightly. While still hot, sprinkle with flaky sea salt so it sticks to the surface.

Cool and finish: Let the cookies rest on the pan for several minutes to set, then transfer to a wire rack to cool the rest of the way. Repeat with the remaining chilled dough balls.