Combine chocolate, 1/4 cup of the milk and the sugar replacement in top of double
boiler. (Chill remaining milk in freezer.)
Cook and stir over simmering water until chocolate melts. Pour amount of hot
chocolate mixture over egg yolks and beat well. Pour egg mixture into chocolate
mixture on top of double boiler. Stir in salt. Cook and stir over hot water until
mixture thickens. Cool completely.
Scrape cold or slightly frozen milk into mixing bowl and beat until very stiff.
Fold chocolate mixture into stiffly beaten milk. Fold in vanilla extract and banana
Spoon into mold, freezer tray or individual cups, and freeze until firm.