Place egg whites in a large bowl; let stand at room temperature 30 minutes.
Meanwhile, preheat oven to 350°. In a small bowl, mix flour and coffee granules until blended.
Add cream of tartar, extract and salt to egg whites; beat on medium speed until soft peaks form. Gradually add sugar, 1 tablespoon at a time, beating on high after each addition until sugar is dissolved. Continue beating until soft glossy peaks form. Gradually fold in flour mixture, about 1/2 cup at a time.
Gently transfer to an ungreased 10-in. tube pan. Cut through batter with a knife to remove air pockets. Bake on lowest oven rack 30-40 minutes or until top springs back when lightly touched. Immediately invert pan; cool cake in pan, about 1-1/2 hours.
Run a knife around sides and center tube of pan. Remove cake to a serving plate. In a small bowl, whisk Nutella, confectioners' sugar and coffee until smooth. Drizzle over cake; sprinkle with hazelnuts. Serve with cherries.