Rhubarb Crunch

1 cup all-purpose flour

1 cup old-fashioned oats

1 cup packed brown sugar

1 teaspoon ground cinnamon

1/2 cup cold butter, cubed

4 cups diced fresh rhubarb or frozen rhubarb

1-1/3 cups sugar

2 teaspoons cornstarch

1 cup cold water

1 teaspoon vanilla extract

Vanilla ice cream, optional

Directions:

In a large bowl, combine the first four ingredients. Cut in butter until mixture resembles coarse crumbs. Press half of the mixture into a greased 8-in. square baking dish. Set remaining crumb mixture aside for topping. Sprinkle rhubarb over crust; set aside.

In a small saucepan, combine the sugar and cornstarch; gradually whisk in water until smooth. Bring to a boil; cook and stir for 2 minutes or until thickened.

Remove from the heat, whisk in vanilla. Pour over rhubarb. Sprinkle with reserved crumb mixture.

Bake, uncovered, at 350° for 1 hour or until bubbly and lightly browned. Serve warm with ice cream if desired.