Heat oven to 350°F. Spray 15x10x1-inch baking pan with no-stick cooking spray. Line bottom of pan with parchment paper. Spray paper and sides of pan lightly with no-stick cooking spray. Set aside.
Beat egg whites in bowl at high speed, scraping bowl often, until stiff peaks form. Set aside.
Combine 2 egg yolks, sugar and butter in another bowl. Beat at medium speed, scraping bowl often, until creamy. Add vanilla; continue beating 30 seconds. Beat at low speed, gradually adding all remaining cake ingredients. Gently stir egg whites into chocolate mixture until well mixed.
Pour into prepared pan; spread evenly. Bake 10-15 minutes or until top springs back when touched lightly in center and cake pulls away from edge of pan. Immediately loosen sides of cake by carefully running sharp knife between cake and paper. Cool 10 minutes.
Invert cake onto smooth cotton dish towel sprinkled with sifted powdered sugar. (Do not use terry cloth towel.) Very carefully remove top piece of parchment paper. (Cake may stick slightly to paper.) Lightly spray 15x10-inch piece of parchment paper and place over cake, sprayed-side down. Roll up cake, while cake is warm, and paper in towel beginning with 10-inch side. Cool completely, seam-side down, about 30 minutes.
Dissolve instant espresso in 1 tablespoon water in bowl; set aside.
Beat whipping cream in bowl at high speed until soft peaks form. Gradually add powdered sugar; continue beating until stiff peaks form. Gently stir in dissolved espresso and grated chocolate.
Carefully unroll cake; remove top piece of parchment paper. Evenly spread filling over cake. Roll up cake from 10-inch end by carefully lifting towel, ending with seam-side down. Sprinkle cake with sifted powdered sugar. Trim edges, if necessary. Carefully place onto serving plate. Cover; refrigerate until serving time. Garnish with chocolate-covered coffee beans, if desired. Carefully cut slices using sharp serrated knife.