Frosted 7 Up Salad

2 3 ounce packages lemon jello
2 cups boiling water
2 cups 7 up
1 20 ounce can crushed pineapple...drained...SAVE JUICE
1 cup miniature marshmallows
2 bananas...sliced
1/2 cup sugar
2 tablespoons flour
1 cup pineapple juice
1 egg...beaten
2 tablespoons butter
2 cups whipped cream

Dissolve jello in water. Add 7 up. Let partially set. Add drained pineapple, marshmallows and bananas. Chill til set. Cook sugar, flour, pineapple juice and egg in a saucepan til thick., Remove from heat. Add butter. Cool. Fold in whipped cream. Top the salad with the whipped cream mixture.