Instructions

• Preheat oven to 400°F (200°C). Line a muffin tin with paper liners.
• In a large bowl, whisk together the flour, granulated sugar, brown sugar, baking powder, baking soda, and salt.
• In a separate bowl, whisk together the buttermilk, oil, egg, and vanilla extract.
• Add the wet ingredients to the dry ingredients and stir until just combined. Gently fold in the diced rhubarb.
• Prepare the crumb topping: In a small bowl, combine the flour and sugar. Cut in the cold butter using a pastry blender or your fingers until the mixture resembles coarse crumbs.
• Fill each muffin liner about 2/3 full. Sprinkle crumb topping over each muffin.
• Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
• Let cool in the muffin tin for a few minutes before transferring to a wire rack to cool completely.