- 9 ounces confectioners' sugar
- 1/4 teaspoon salt
- 1 teaspoon espresso powder, optional but good
- 3 ounces cocoa powder, Dutch-process (European-style) preferred*
- 3 large egg whites
- 2 teaspoons gluten-free vanilla extract
- 2 cups finely chopped walnuts (optional)
- *For darker, richer-looking cookies, substitute 1/4 cup black cocoa for 1/4 cup of the Dutch-process cocoa