Combine flour, baking soda, and salt. In another bowl combine brown sugar and oil. Add egg, milk and vanilla. Stir into dry mixture with rhubarb until flour is incorporated. Spoon into greased or lined muffin tins or 2 greased 4" x 8" loaf pans. Combine topping and sprinkle over batter. Bake at 350 F for 20-25 minutes for muffins or 40-45 minutes for loaf. Cool 10 minutes in pan. NOTES : I like to substitute soured milk in place of the buttermilk. Recipe by: Canadian Living Magazine Posted to MC-Recipe Digest V1 #587 by Shelly on Apr 25, 1997