Nana's Jello Salad

3 cups boiling water
1 lg. pkg. lemon jello
1 lg. can crushed pineapple
2 cups mini marshmallows
3 sliced bananas
Topping:
½ cup sugar
1 egg, beaten
1 ½ Tbs. flour
1 cup pineapple juice
1 sm. whipping cream

Drain pineapple. Save juice. Dissolve jello in water and add all other ingredients. Chill until set. Boil pineapple juice, sugar, flour, and beaten egg until thickened. Stirring constantly. Chill until cool. Whip cream and fold into topping mixture. Spread on set jello and top with finely grated cheddar cheese.