Rhubarb recipe with 5 ingredients - I made this last night and it's wonderful! 1 egg 4 Tbsp flour (GF works fine) 4-5 c rhubarb chopped Mix above in bowl, place in greased glass pan. Sprinkle yellow cake mix (GF is fine) over top of this. Melt 1.5 sticks of butter and pour over the top. 350° for 40-45". would be good with cinnamon/sugar on top, too.