My mom used to make this when I was little.
5 c rhubarb, chopped
3 c sugar
1, 6oz pkg strawberry (or cherry) Jello
1 T butter
Combine rhubarb with sugar and let sit overnight. Next day, add butter and cook mixture for 10 minutes on med to med-high heat. Remove from heat. Stir in Jello. Place in glass jelly jars. Refrigerate or freeze until you want to use.