1 1/2 c. flour
1 c. sugar
1 tsp. baking soda
1 c. sour cream
2 c. rhubarb, cut in 1/2-inch pieces

Topping:

1 tsp. cinnamon
1/2 c. chopped walnuts
2 1/4 c. flour
1 1/2 c. sugar
1 1/2 tsp. baking soda
1 1/3 c. sour cream
2 eggs
3 c. rhubarb

Sift together flour, 1 cup sugar and baking soda. Mix sour cream and egg well. Combine sifted ingredients with sour cream mixture until blended. Add rhubarb. Spread in 9 x 13-inch pan. Mix sugar, cornstarch and nuts. Sprinkle over mixture in cake pan.

Bake at 350°F for 30 minutes.

If you want to make more squares, use a jelly roll pan and these measurement changes: