Using a stand mixer fitted with a whisk attachment or a hand mixer, whisk eggs, granulated sugar, and brown sugar on high speed for 5 minutes. Add chocolate mixture and mix on low speed just until combined. Add flour mixture and mix just until combined. Use a rubber spatula to scrape the sides and bottom of the bowl. The mixture will be soft, so place it in the fridge for 1-2 hours until it firms up a bit.
Using an ice cream scoop drop rounded balls of dough (or about 2 tablespoons, you should get 16-18 cookies) onto a prepared baking sheet, leaving 3 inches between each cookie to allow spreading. Sprinkle each cookie with a little flaked sea salt, if desired.