1 C. oatmeal
1 C. flour
1 C. brown sugar, packed
1/2 C. butter or margarine
1 C. sugar
1 C. water
3 T. cornstarch
1 tsp. vanilla
Mix oatmeal, flour, brown sugar and butter/margarine. Spread 1/2 of mixture in the bottom of an 8×8″ pan. Evenly spread chopped rhubarb over crust. Combine sugar, water and cornstarch in a saucepan. Boil and stir until thick and bubbly. Remove from heat. Add vanilla and pour over rhubarb. Sprinkle remaining crumb mixture on top.
Bake at 350º for 1 hour.