1 c. sifted flour
3/4 c. oatmeal
1 c. brown sugar, packed firm
1/2 c. melted butter
1 tsp. cinnamon
4 c. diced rhubarb
1 c. sugar
2 tbsp. cornstarch
1 c. water
1 tsp. vanilla

Mix first 5 ingredients until crumbly. Press 1/2 of mixture into a greased 9 x 13 inch pan. Cover with 4 cups diced rhubarb. Then combine sugar, cornstarch, water and vanilla in saucepan. Cook over medium heat until thick and clear. Pour over rhubarb. Then top with the remaining crumb mixture. Bake at 350 degrees for 45 minutes to 1 hour, or until bubbly. Serve warm or cold with ice cream or whipping cream.