When ready to cook, set grill temperature to 375º and preheat, lid closed, for 15 minutes.
In a medium bowl, combine the dry ingredients and whisk well.
Add butter and both sugars to bowl of a stand mixer and mix with the paddle attachment on medium speed for 3-4 minutes, until the mixture becomes light in color and sugar is incorporated into the butter.
Add eggs one at a time, waiting until the first is incorporated before adding the next, followed by the vanilla.
Reduce speed to medium low, and add flour mixture in three parts. When just incorporated, add chocolate chips, and mix 15 seconds longer.
Line two half sheet trays with parchment paper. Using a six-ounce scoop, portion cookie dough out, placing four cookies on each sheet tray. Keep them mounded up high, as this will result in a chewy, doughy center but cooked exterior. Sprinkle the top with additional sea salt, if desired.
Place sheet trays directly on grill grate and bake 20-25 minutes, until the outside is lightly browned. Cookies will look a little underdone (exterior will be lightly browned, but center will still look gooey) which is what you’re shooting for.
Remove them from grill and let sit at room temperature for 10 minutes to set up. Enjoy!