Preheat oven to 350°F (180°C) and line 1 large or 2 medium baking sheets with parchment paper. Measure all ingredients before starting.
Melt butter and chocolate in a small saucepan over low heat, stirring constantly. Set aside.
In a stand mixer or using an electric mixer, whisk eggs and both sugars on medium speed for 5 minutes. Slowly add melted chocolate and mix for 1 minute.
Mix dry ingredients in a bowl, then gently fold them into the chocolate mixture until just combined. Scrape the bowl to ensure everything is mixed.
Scoop dough onto prepared baking sheets, leaving space between cookies as they spread.
Sprinkle sea salt on top and bake for 10-12 minutes until crinkled and domed.
Let cookies cool on the tray for 20 minutes before moving, as they’ll be very soft.