You will need a 9 x 13 baking dish.
1st layer - small white marshmallows - enough to cover the bottom of the pan in a single layer.
2nd layer - white cake batter
1/4 cup of oil
2/3 cup of white sugar
2 medium eggs
1 tsp. vanilla extract
1 1/2 cups of flour
2 tsp. baking powder
1/2 tsp. salt
2/3 cup milk
3rd layer - fruit mix, combine in a saucepan and bring to a boil:
4 cups of rhubarb, or rhubarb & strawberries mixed together
1 cup of water
1 scant cup of white sugar, less if you are using sweet strawberries
1 - 3 oz. package of strawberry jello mix (the small box)
Pour the cake batter over the marshmallows, then spoon the fruit mix over the cake batter. Bake at 350° for 30 minutes. Let it cool before serving, otherwise it will be really runny.