Combine the chocolate,1/4 cup (60 mL) of the milk and the sugar replacement into the top of a double boiler (chill the remaining milk in the freezer)
Cook and stir over simmering water until the chocolate melts.
Pour an amount of hot chocolate mixture over the egg yolks and beat well
Pour the egg mixture into to the chocolate mixture on top of double boiler.
Stir in the salt and Cook and stir over hot water until mixture thickens.
Cool completely.
Scrape cold or slightly frozen milk into a mixing bowl and beat until very stiff..
Fold chocolate mixture into stiffly beaten milk..
Fold in vanilla and banana slices.
Spoon intofreezer tray or individual cups and freeze until firm