1 1/2 c. oatmeal
1 c. brown sugar
1 c. butter
1/2 tsp. baking soda
1 1/2 c. flour
1/2 c. chopped nuts

Mix together and pat 3/4 of mixture in 9x13 pan.

RHUBARB FILLING:

3 c. cut-up rhubarb
3 tbsp. cornstarch
1 tsp. vanilla
1 1/2 c. sugar
1/4 c. water

Dissolve cornstarch in water, then add rest of ingredients. Mix and cook until thick. Pour rhubarb mixture over crust and sprinkle remaining crumb mixture on top. Bake 30-35 minutes at 350 degrees.