Ingredients:
1 ½ cups brown sugar
⅔ cup vegetable oil
1 large egg
1 cup buttermilk (or 1 tbsp vinegar + milk to make 1 cup)
1 tsp vanilla extract
2 ½ cups all-purpose flour
1 tsp baking soda
½ tsp salt
1 ½ cups diced rhubarb
½ cup chopped nuts (optional – walnuts or pecans)
1 tbsp melted butter + 2 tbsp sugar + ½ tsp cinnamon (for topping)
Instructions:
Preheat oven to 350°F (175°C). Grease a 9×5-inch loaf pan or line with parchment.
In a large bowl, whisk together brown sugar, oil, egg, buttermilk, and vanilla.
In a separate bowl, mix flour, baking soda, and salt.
Add the dry ingredients to the wet ingredients and stir just until combined.
Fold in the diced rhubarb and nuts (if using).
Pour into the prepared pan. Mix topping ingredients and sprinkle over the batter.
Bake for 50–60 minutes, or until a toothpick comes out clean.
Cool in the pan for 10 minutes, then transfer to a wire rack.