- Preheat oven to 370°F.  Line a baking sheet with parchment paper. Mix dry ingredients and set aside. 
- Cream butter with sugars in a mixer in a stand mixer, or with a hand mixer on medium speed. Mix until fluffy. 
- Add in egg, egg white, and vanilla and mix until well incorporated. 
- Slowly add combined dry ingredients then chocolate, including the chocolate powder/dust. (It's okay if some of the chopped chocolate cracks in the mixer. It will spread nicely throughout the cookies.) 
- With a large cookie scoop measuring 1/3 cup in size (or a 1/3 cup measuring scoop), scoop large rounds of the cookie dough onto parchment-lined sheet. Scoop out all the dough into even cookie dough balls of about 1/3 cup in size. You will be freezing all the cookie dough balls on this sheet until solid. 
- Once cookie dough balls are frozen solid (it will take about 20 minutes), remove and place 5-6 large cookie dough balls on a clean, parchment-lined baking sheet. Return unused cookie dough to freezer - you want to bake these straight from the freezer so they don't spread too much. 
- Bake for 10 minutes in preheated oven, then remove and gently drop the pan onto the stovetop. This helps get the bakery-style crinkles on the top of the cookie. 
- Then, return to the oven and bake for 4-6 more minutes until the tops are evenly golden brown.  
- Once golden brown, remove from oven and gently drop pan one more time on the stovetop, for a couple more crinkles on top. 
- Sprinkle each cookie with a little flake salt .Let set for 3-4 minutes then enjoy!