This bread has a delicate taste that goes well with the acidity of the rhubarb.

Set the oven rack in the lower third of the oven. Preheat oven to 180°C (350°F). Grease two 13 cm x 23 cm (5 inches x 8 inches) loaf pans.
In a large bowl, beat the egg until there are no traces of egg white. Add the brown sugar and beat until blended.
Add the oil, buttermilk, and vanilla extract and beat until blended.
In a medium bowl, whisk together the flour, salt, baking powder, soda, and cinnamon and add this mixture to the batter and beat until smooth. Stir in the rhubarb and walnuts.
Pour batter in prepared pans and bake 40 to50 minutes until a tooth pick inserted in the center of the bread comes out clean. Place bread on a rack and let cool 5 Minutes before unmolding. Cool completely before serving.