This recipe originated with a 1930s Kelvinator cookbook I bought at a flea market. The recipe is a lot of trouble to make but it can be prepared in advance when you have time. Pasteurized egg whites are recommended as this dish is not cooked.
1 small banana
1/2 tbs lemon juice
1 egg white
2 tbs powdered (confectioners) sugar
1 drop yellow food color (optional.)
Mash the banana very thoroughly, so that there are no lumps -- the original cookbook says to force it through a strainer. Nowadays we could also puree it in a food processor. Add the lemon juice to the banana pulp, and the food color if desired.
Beat the egg white till soft peaks form, then add the sugar and beat stiff.
Finally, combine the egg mixture and the banana mixture, stirring together gently but thoroughly. Place into serving dish and freeze for at least 40 minutes before serving.