Mix the following until crumbly:
1 C flour
3/4 C oatmeal
1 C packed brown sugar
1/2 C melted butter
1 tsp cinnamon
Press half of crumbs in a greased 9" pan.
Cover with 4 Cups diced rhubarb.
Combine the following in a saucepan.
1 C sugar
1 C water
2 Tbl cornstarch
1 tsp vanilla
cook until thick and clear.
Pour over rhubarb layer.
Top with remaining crumb mixture.
Bake at 350 for 1 hour.
