Add egg and beat well.
Sift dry ingredients and add alternately with buttermilk.
Fold in rhubarb and nuts.
Spoon into well greased bundt pan. Bake at 350° for 40-45 minutes.
Cool 10 minutes.
Turn out to finish cooling.
OPTIONAL: Topping may be made by 1/3 cup sugar and 3/4 Tablespoon cinnamon sprinkled on top of batter. Try this with apples as well as rhubarb.