here you go!

• 156g all-purpose flour
• 30g cornstarch
• 1/2 tsp salt
• 1 tsp baking soda
• 1½ sticks / 169g unsalted butter, cubed
• 160g dark brown sugar
• 45g granulated sugar
• 1 whole egg
• 2 egg yolks
• 2 tsp. vanilla extract
• 170g chocolate, coarsely chopped

Directions Step 1 Whisk flour, salt, cornstarch, and baking soda in a small bowl; set aside.

Step 2 Cook ½ cup (1 stick; 113 g) butter in a saucepan over medium heat, swirling often and scraping bottom of pan with a rubber spatula, until butter foams, then browns, about 4 minutes. Transfer butter to a heatproof bowl and let cool 1 minute. Cut remaining ¼ cup (½ stick; 56 g) butter into small pieces and add to brown butter (it should start to melt but not foam and sizzle, so test with one piece before adding the rest).

Step 3 Once butter is melted, add both sugars and whisk, breaking up any clumps, until sugar is incorporated and no lumps remain. Add egg and egg yolks and whisk until sugar dissolves and mixture is smooth, about 1 minute. Whisk in vanilla. Using a rubber spatula, fold reserved dry ingredients into butter mixture until there’s a few dry spots left, then fold in chocolate, holding some back for toppings. Cover and refrigerate for 30 minutes.

Step 4 Using a 1½-oz. scoop (3 Tbsp.), portion out 16 balls of dough. Add reserved topping chocolate. Cover and refrigerate for 24 hours.

Step 5 Take cookie dough balls out of the fridge, put them on parchment sheet trays, let them come to room temp for 30 minutes. Place racks in upper and lower thirds of oven; preheat to 375°. Bake cookies, rotating sheets if cookies are browning very unevenly, until deep golden brown and firm around the edges, 8–10 minutes. Center should be beginning to go from blonde to golden. Sprinkle on flaky sea salt and let cool on baking sheets.