1½ tbsp. instant espresso powder or instant coffee
1 tsp. pure vanilla extract
cocoa for dusting
Optional: coffee beans
Preheat oven to 250 degrees Fahrenheit. Line a baking sheet with parchment paper and set aside.
In a large mixing bowl, beat the egg whites, salt and cream of tartar with an electric mixer (fitted with the balloon whisk attachment) on medium speed until the whites are foamy. Increase speed to high, beating until soft peaks form. Slowly add in the sugar, adding about 2 tablespoons at a time, beating for 15-30 seconds after each addition. Add the espresso and vanilla; continue to beat until the meringue forms very stiff, shiny peaks when the beaters are raised.
Working quickly, drop the mixture by large spoonfuls onto the prepared baking sheet, spacing them 1-2 inches apart. Top each meringue with optional coffee bean and dust with cocoa.
Bake for 1 hour or until the surfaces of the meringues feel dry and you can pick one off the parchment without any sticking.
Turn off oven, prop the door open slightly with the handle of a wooden spoon, and allow meringues to cool gently in the oven for 1 hour. Transfer to a serving platter.