Ingredients:

5 c. chopped rhubarb
3/4-1 c. sugar
1 lg. pkg. strawberry Jell-O

3 c. miniature marshmallows
1 yellow cake mix

Directions:

In order given, layer first 4 ingredients in greased 13 x 9 pan.
Use Jell-O straight from the box.
Mix cake mix according to pkg. directions.
Pour into pan over the top of the other ingredients.  
Bake at 350ºF for 40-50 minutes, or till cake appears done.
Serve from pan, or, freeze in pan.  
Or, invert onto cake plate 10 minutes after removing from oven.  
Then freeze or serve topped with whipped cream.