Beat egg yolks until light; add sugar gradually.
Beat until thick and lemony; add chocolate.
Soften gelatin in 1 tablespoon cold water; dissolve in 5 tablespoons boiling water.
Add gelatin mixture to chocolate mixture; blend thoroughly.
Beat egg whites until stiff peaks form; fold into chocolate mixture.
Pour into mold; chill until firm.
Serve with whipped cream, if desired.