1Preheat oven to 350^. Combine milk, baking soda, salt & vanilla in small bowl; mix well.
Combine brown sugar, oil & egg in mixer bowl; mix well.
Add milk mixture alternately with flour, mixing well after each addition. Stir in rhubarb. Spoon into greased and floured loaf pan.
Sprinkle with mixture of melted butter & sugar.
Bake for 1 hour.