preheat oven to 350˚F. Line cookie sheets with parchment paper.
Place egg whites, powdered sugar, cocoa powder, flour, vanilla, and salt in an electric mixer; Stir in a low speed until everything is blended. Beat at high speed for 1 minute. Stir in pecans.
Drop heaping tablespoons on a lined cookie sheet, leaving 2-inches apart, and bake for 15 minutes.
Let the cookies cool on the cookie sheet for 5 minutes than transfer to a rack to cool completely.
Store the cookies in an airtight container or a zip bag. To freeze, put them in an airtight zip bag and freeze up to 3 months.