Combine in large saucepan. Bring to boil, reduce heat and simmer 4 minutes, stirring.
¼ cup water
3 Tbsp cornstarch
Dissolved cornstarch in water and add to rhubarb, stirring constantly until thickened.
1 ½ cups flour* (or part oat bran*)
1 ½ cups rolled oats*
¾ cup brown sugar
¾ cup butter*
½ tsp salt
½ tsp ground cinnamon
½ cup walnuts or other nuts, chopped
Mix together until crumbly. Place about 3 ½ cups of crumb mix into greased 9x13’ baking pan and press to make an even layer. Pour in rhubarb/sorrel mix and spread evenly. Sprinkle with remaining crumb mixture over top. Bake in preheated oven at 350 F for 30-40 minutes. Cut into squares.
