Adjust oven racks to divide oven into thirds. Preheat oven to 250 degrees F. Beat egg whites, cream of tartar, and salt with a mixer at high speed until foamy. Add sugar, l tablespoons at a time, beating until stiff peaks form. Add espresso and vanilla, beat until well blended.
Cover 2 baking sheets with parchment paper ; secure to the baking sheets with masking tape. Drop batter by level tablespoon onto prepared baking sheets. Top each mound with 1 coffee bean. Sprinkle evenly with cocoa. Bake at 250 degrees F. for 2 hours or until dry. (Meringues are done when the surface is dry and meringues can be removed from paper without sticking to fingers). Turn oven off, and partially open the oven door; leave meringues in oven 1 hour. Remove from oven; carefully remove meringues from paper. Cool completely on wire racks. Note: Do not use egg substitute in place of egg whites.