1 c. flour
1 c. oatmeal
1 c. brown sugar
1/2 c. butter, melted
4 c. finely cut rhubarb
1 c. sugar
1 c. water
2 tbsp. cornstarch
1 tsp. vanilla

Combine first 4 ingredients; mix like pie crust. Press 1/2 mixture into a 9 inch square baking pan. Cover oat mixture with rhubarb. Combine sugar, water, cornstarch and vanilla. Cook over medium heat until thick and clear. Pour over rhubarb. Cover with the remaining crumbs. Bake at 350 degrees for approximately 45 minutes or until rhubarb is done.