Cut up rhubarb in 9x13-inch pan. Sprinkle with strawberry or raspberry jello. Spread on sugar and marshmallows. Mix cake mix as directed and spread. ... to tray or platter.
Put butter in large oblong pan, add rhubarb, add marshmallows. Mix Jello and sugar, sprinkle on pan ... and egg with cake mix, pour over top of ... minutes. May serve warm.