Preheat oven to 425.
In stand mixer, or large mixing bowl, cream 1/3 cup softened butter, 1/4 c turbinado sugar, 1/4 c dark brown sugar by mixing it together on medium speed. Mix for 2-3 minutes, or until well incorporated.
One butter and sugar are combined, turn off mixer, and add 1 medium sized egg. Mix until incorporated.
Add 3/4 c all purpose flour, 1 Tbsp dark cocoa powder, 1/4 tsp each baking powder and soda, 1/8 tsp salt to mix. Mix together on low, until flour is all incorporated.
Add 1 cup semi sweet chocolate chips to cookie dough. Fold into dough with a rubber spatula.
Divide dough into 5-6 large pieces. Form each piece into a round ball, and place, evenly spaced out, on a large cookie sheet with a silicone mat or parchment paper. Sprinkle a pinch of flaky salt on each cookie.
Bake for 5-6 minutes in the middle of the oven. Cookies will be gooey, and shiny, but the dough won't look wet. Sprinkle a pinch of flaky salt on each cookie. Using a rubber spatula, push in edges to form a cookies with even thickness throughout. Let sit to cool for at least 10-15 minutes.
Serve with milk.