8 C rhubarb, chopped into 1″ pieces
1 C margarine
2 C flour (or ground oats, or GF flour)
1-1/2 C oatmeal
2 C brown sugar
2 tsp cinnamon
1 C sugar
2 Tbsp cornstarch
1 C water
1 tsp vanilla
Measure sugar for sauce into a dry bowl, then thoroughly stir in cornstarch until no lumps remain; add liquids and cook until thick.
In separate bowl, melt margarine, then mix in remaining crunch ingredients. Press half of crunch onto bottom of 9×13 pan.
Top crunch crust with chopped rhubarb and pour thickened sauce over fruit. Crumble remaining crunch over the top. Bake at 350 degrees for 60 minutes.