Preheat oven to 350 degrees. Line baking sheet with parchment paper, or foil sprayed with non-stick cooking spray.
Mix together powdered sugar, cocoa powder, salt and baking powder in a bowl. Place egg whites and milk in another small bowl, and stir to combine. Mix wet and dry ingredients together, until just combined, but don’t over beat.
Using a tablespoon, scoop up cookie batter, and use a teaspoon to drop cookie batter onto prepared baking sheet. Sprinkle peppermint chips on cookies, dividing evenly between cookies.
Bake cookies for 15 minutes, and enjoy!