Rhubarb Crisp

Not sure where this recipe came from, but it's delicious:

Rhubarb Crisp

1 cup light brown sugar
1 cup flour
3/4 cup oats
1/2 cup melted butter
1 tsp cinnamon
4 cups rhubarb
1 cup sugar
2 Tbsp cornstarch
1 cup water
1 tsp vanilla

Combine the first five ingredients, mixing until crumbly.  Press 1/2 into an 8 inch dish.

Top with chopped rhubarb.

Cook the remaining four ingredients in saucepan until clear.  Pour over rhubarb.

Top with remaining crumb mixture.  Bake 350 F for 35-55 minutes.