In a large heatproof bowl, add the butter and chocolate. Warm in the microwave for 1 minute, then stir and heat for another minute. Stir until chocolate and butter is fully melted and smooth.
Add the sugars, set the bowl back in the microwave for another minute. Whisk very vigorously, the mix will look a bit separated.
Add the eggs and whisk again, for a full minute, until the batter is smooth and shiny.
Add the remaining ingredients and stir to combine.
Set the bowl, uncovered, in the fridge for at least 4 hours (this is important for crispy edges) or overnight.
Preheat the oven to 350 F. Line two greased cookie sheets with parchment paper. Portion the cookie dough into about 1.5-2 tablespoons each onto the sheet.
Bake for 10-12 minutes.