Soften gelatin in cold water, let stand 5 minutes.
Combine milk, chocolate morsels, and cocoa in a heavy saucepan, cook over low heat until chocolate melts.
Combine egg yolks and sugar in a small mixing bowl, blend well.
Gradually stir about one-fourth of hot mixture into egg yolk mixture, add to remaining hot mixture, stirring constantly.
Add coffee granules to hot mixture.
Cook, stirring constantly, until mixture thickens.
Remove from heat and stir in softened gelatin and vanilla.
Chill until mixture is the consistency of unbeaten egg white.
Beat egg whites (at room temperature) until stiff peaks form.
Gently fold egg whites into coffee mixture.
Gently fold whipped cream into egg white mixture.
Spoon into a 1-quart casserole, and chill until firm.
To serve, top with additional whipped cream and chocolate shavings, if desired.