Directions

1. Combine the ground nuts, cocoa, lemon peel, salt, and vanilla in a small bowl.
2. In a large bowl, beat the egg whites until they foam and thicken slightly. Sprinkle the sugar over them, and continue to beat until whites form stiff, unwavering peaks on the beater when lifted out of the bowl. Gently fold the nut mixture into the whites until thoroughly combined.
3. Coat a large baking sheet with 2 teaspoons softened butter. Drop the dough by tablespoons onto the prepared baking sheet, spacing them about an inch apart. Let the cookies rest at room temperature for 1 hour before baking.
4. Preheat the oven to 300 degrees F (150 degrees C). Place the cookies in the middle of the oven; bake for 30 minutes, or until they are firm. With a spatula, carefully transfer the cookies to a rack to cool.