01 -
Preheat oven to 163°C. Grease two 20×10 cm loaf pans or line them with parchment paper.
02 -
In a large bowl, whisk together brown sugar, vegetable oil, egg, buttermilk, and vanilla extract until the mixture is smooth.
03 -
In a separate bowl, blend all-purpose flour, baking soda, and salt.
04 -
Gradually incorporate the dry mixture into the wet ingredients, stirring only until combined.
05 -
Gently fold in diced rhubarb and chopped walnuts until evenly distributed.
06 -
In a small bowl, blend granulated sugar and ground cinnamon.
07 -
Distribute the batter equally between the prepared loaf pans. Sprinkle the cinnamon-sugar mixture evenly across both loaves.
08 -
Bake for 55–60 minutes, or until a toothpick inserted into the centre emerges clean.
09 -
Allow the loaves to cool in the pans for 10 minutes before transferring to a wire rack to cool completely.