Preheat the oven to 350°F. Line a baking sheet with parchment paper.
In a medium sized bowl, combine the flour, cocoa powder, baking powder, and salt. Stir with a whisk to combine.
1 ⅓ cups flour, ½ cup Dutch process cocoa powder, ½ teaspoon baking powder, ¼ teaspoon salt
In a separate medium sized bowl, add the egg whites. Using a hand mixer, beat on medium speed for about 30 seconds or just until they are beginning to froth.
4 egg whites, about ½ cup
Add the sugar, vegetable oil and vanilla. Beat on medium speed just until combined.
1 ¼ cups sugar, ⅓ cup vegetable oil, 1 teaspoon vanilla
Add the flour mixture to the egg white mixture and beat just until combined.
Using a rubber spatula, fold in 1 cup of the chocolate chips.
1 ¼ cup semi-sweet chocolate chips
Place the bowl in the refrigerator for 10 minutes to chill.
Using a medium sized cookie scoop (about 1 ½ tablespoons), portion out dough onto the prepared baking sheet, leaving about 2 inches between each cookie.
Sprinkle the tops with flake salt and bake in the prepared 350°F oven for 9-11 minutes.
Remove the cookies from the oven and top with additional chocolate chips by gently pressing them into the tops. Let the cookies cool on the baking sheet for 2 minutes before transferring to a cooling rack to cool completely.