Preheat oven to 350 degrees.
In a large mixing bowl whisk together powder sugar, unsweetened cocoa powder, cornstarch and sea salt. Once well combined mix in egg whites, egg and vanilla until completely combined and batter is smooth. Fold in all of the chocolate chips but 2 tablespoon of the 60% cocoa chocolate chips.
Scoop onto baking sheet prepared with parchment paper; 6 large cookies or 8 regular cookies.
If you are making large cookies, do 1 very generous scoop, then use your finger to make the dough into a perfect circle. If you are making regular cookies, just do 1 cookie dough scooper full and make sure to spread the cookie with your finger in a perfect circle.
Top 3-4 chocolate chip from the 2 tablespoons of chocolate chips set aside on top of each cookie.
Place in pre-heated oven and bake for 12-16 minutes, depending on your cookie size.
12-14 minutes for normal sized cookies, makes 16 cookies
16 minutes for generous sized cookies, makes 9 cookies
Remove from oven and cookie on cooling rack for 3-5 minutes.