Preheat oven to 275°F. Line 2 cookie sheets with parchment paper.

Toast walnuts on a cookie sheet at 400 for 5 to10min. Watch carefully, because they go from perfect to burnt quickly.

In a medium, clean, grease-free bowl with an electric mixer on high speed, whip egg whites until foamy. Add cream of tartar and whip until soft peaks form. Gradually add sugar, salt, cocoa, espresso powder then vanilla whipping until stiff but not dry peaks form. Blend in walnuts. Drop by generously rounded teaspoon 2 inches apart on cookie sheets.

(Jane says to beat everything but the walnuts first. But not to the point of increasing volume. Not the point. Then beat in walnuts. She bakes on 335 for 10 minutes, maybe a bit more.)

Bake until firm and dry, but still light in color, about 25 minutes. Tops should be cracked and shiny and you should be able to lift cookies from pan. Slide parchment onto racks to cool cookies completely.