Rhubarb Cake

1/2 c. butter
1 tsp. baking soda
1 c. brown sugar
2 c. rhubarb, diced
1 tsp. salt
1 c. milk
1 egg
2 c. flour
1 tsp. vanilla
1/2 c. nuts (optional)
1/2 c. brown sugar
1 tsp. cinnamon

Preheat oven to 350 degrees. In a large bowl, mix together butter, baking soda, 1 c. brown sugar, salt, egg, milk, flour, vanilla, and rhubarb. Pour cake mixture into a greased 13x9x2-inch baking dish. In a small bowl, combine 1/2 c. brown sugar, nuts, and cinnamon. Sprinkle on top of cake mixture. Bake for 45 minutes.