No idea where I got this recipe, but it was good!
Flourless Chocolate-Walnut Cookies
2 1/2 cups walnut halves, chopped
3 cups confectioner's sugar
1/2 cup plus 3 tablespoons unsweetened cocoa powder
1/2 teaspoon salt
4 egg whites
1 tablespoon vanilla
Position two racks in the upper and lower thirds of the oven. Heat oven to 350 degrees. Line two large baking sheets with parchment paper. Place walnuts on a work surface and finely chop. Transfer to a separate large baking sheet and toast until fragrant, about 9 minutes.
Mix sugar, cocoa, and salt in a bowl. Stir in walnuts. Add egg whites and vanilla; beat until batter is just moistened (overbeating will stiffen). Drop batter by the teaspoonful onto backing sheets in evenly spaced mounds. Bake cookies until tops are lightly cracked and glossy, about 10 minutes. Repeat with remaining batter. Store in an airtight container at room temperature up to one week.