2-1/2 cups flour
1 teaspoon baking soda
1 teaspoon salt
1-1/2 cups brown sugar
1 cup buttermilk
1 beaten egg
2/3 cup vegetable oil
1 teaspoon vanilla extract
1-1/2 cups chopped rhubarb
1/2 cup chopped walnuts
Preheat oven to 325 degrees. Spray a glass 9x13x2-inch pan.
In a large mixing bowl, sift together flour, baking soda, and salt. Stir in brown sugar and set aside. In another bowl, mix buttermilk, egg, vegetable oil, and vanilla extract. Add rhubarb and walnuts, stirring until blended. Add wet ingredients to dry ingredients and stir, just until combined. Spread into prepared pan and bake 55 minutes.