Ingredients:

  • 2.5 cups fresh rhubarb, diced into 1/2-inch pieces
  • 2 cups all-purpose flour, spooned and leveled
  • 1 tablespoon all-purpose flour, reserved for coating fruit
  • 0.5 cup rolled oats
  • 1 teaspoon baking powder
  • 0.5 teaspoon baking soda
  • 0.5 teaspoon sea salt
  • 1 teaspoon ground cinnamon
  • 0.5 cup unsalted butter, melted and cooled
  • 1 cup light brown sugar, packed
  • 1 large egg, room temperature
  • 1 cup full-fat sour cream
  • 1 teaspoon pure vanilla extract
  • 3 tablespoons granulated sugar
  • 0.5 teaspoon ground cinnamon, for topping

Instructions:

  1. Preheat oven to 400°F (200°C). In a small bowl, toss diced rhubarb with 1 tablespoon of flour until evenly coated to prevent sinking.
  2. In a large mixing bowl, whisk together the melted butter and brown sugar until smooth. Add the egg, sour cream, and vanilla extract, whisking vigorously until the mixture is pale and fully emulsified.
  3. Sift the 2 cups of flour, oats, baking powder, baking soda, salt, and 1 teaspoon of cinnamon into the wet mixture. Use a silicone spatula to fold the ingredients together until just combined; do not overmix.
  4. Gently fold the flour-coated rhubarb into the batter. The batter should be thick and high-viscosity.
  5. Divide the batter into a 12-cup lined muffin tin. In a small bowl, mix the 3 tablespoons of granulated sugar with 0.5 teaspoon cinnamon and sprinkle generously over the tops.
  6. Bake for 20 minutes or until a toothpick inserted into the center comes out clean and the tops are mahogany-colored and domed.
  7. Cool in the pan for 5 minutes before transferring to a wire rack.