• Preheat oven to 350° F.
• Line 2 baking sheets with parchment paper.

Prepare walnuts

• Spread walnuts on the third baking sheet.
• Toast walnuts in over for approx. 9 minutes, until golden and fragrant.
• Let nuts cool slightly.
• Transfer nuts to work surface and chop finely.

Prepare dough

• In large bowl, whisk together confectioners' sugar, cocoa powder, and salt.
• Whisk in walnuts.
• Add egg whites and vanilla.
• Stir together just until batter is moistened. Do not overbeat of it will stiffen.
• Spoon batter onto baking sheets, 12 mounds per sheet.

Bake

• Bake cookies for approx. 20 minutes, until tops are glossy, lightly cracked, and firm to touch.
• Slide cookies and parchment paper onto wire racks to cool.
• Cool completely before serving.