My aunt's mother made a rhubarb pie that would pull your fillings out (I wish I had the recipe!). We always grew rhubarb in Colorado.
Mix 1 cup sour cream and 1 teaspoon baking soda and let sit
cream together 1 1/2 cups brown sugar, 1/2 cup shortening, and 1 egg.
Combine these two and then add 2 cups of flour, 1 teaspoon vanilla, and 1 1/2 cup (at least) chopped rhubarb. Spread into a greased and floured 9 x 13 pan and top with 1 tablespoon cinnamon and 1/3 cup sugar. Bake at 350 for 30-40 minutes.
NOTE: if that sounds like too much sugar, it might be--we used to eat things sweeter than we do now. I usually skimp, so you can reduce it with no ill effects.