Directions

1. Whisk flour and baking soda in a medium bowl until combined. Using an electric mixer on low speed, beat butter, brown sugar, organic sugar, vanilla, and salt in a large bowl 30 seconds. Add eggs and egg yolk, one at a time, beating well after each addition before adding the next. Increase speed to medium-high and whip until mixture is thick and resembles buttercream frosting, 6-8 minutes.
2. Reduce speed to low (if using a stand mixer, switch to paddle attachment) and beat in dry ingredients, occasionally scraping bottom and sides of bowl, until incorporated. Add chocolate and beat until incorporated. Cover and chill at least 8 hours and up to 12.
3. Arrange racks in lower and upper thirds of oven; preheat to 375°. Let dough come to room temperature. Using a 1-ounce ice cream scoop, portion out dough onto parchment-lined baking sheets, spacing at least 2″ apart (these are large cookies; you probably won’t fit more than 8 per sheet). Flatten cookies slightly with your palm and sprinkle with sea salt. Bake, rotating sheets halfway through, until cookies are just barely golden on the edges but still soft and pale in the center (they will seem undercooked, but they will harden as they sit), 10- 15 minutes. Let cool on baking sheets 5 minutes, then transfer to wire racks and let cool completely.

Do Ahead: Dough can be made 1 day ahead; cover and chill. Bring to room temperature before portioning. Cookies can be baked 2 days ahead; store airtight at room temperature.