Dissolve gelatin in boiling water. Add marshmallows and stir to dissolve. Add soda, slowly and the pineapple with juice and the banana slices-Pour mixture into a 9x13-inch pan. Chill until set. about 4 hours.
In a medium saucepan, mix eggs, sugar, flour and juice. Cook until thick. Cool until cold. Fold in and blend the thawed cool whip. Spread on the set jello mixture. Sprinkle with nuts, if desired.Freeze until needed. To serve, let rest at room temperature for about 15 minutes before cutting and serving...