Ingredients:

  • 1/2 cup (65g) all-purpose flour
  • 1/2 cup (100g) granulated sugar
  • 1 tsp (2g) ground cinnamon
  • 1/4 cup (55g) unsalted butter, cold and cubed
  • 2 cups (250g) all-purpose flour
  • 3/4 cup (150g) granulated sugar
  • 2 tsp (10g) baking powder
  • 1/2 tsp (3g) salt
  • 1 large egg (50g)
  • 1/2 cup (120g) sour cream, full fat
  • 1/2 cup (120ml) whole milk
  • 1/2 cup (120ml) vegetable oil
  • 1 tsp (5ml) vanilla extract
  • 1 1/2 cups (225g) fresh blueberries
  • 1 tbsp flour

Instructions:

  1. In a medium bowl, whisk together the flour, sugar, and cinnamon. Use a pastry cutter or fork to work the cold, cubed butter into the mixture until it forms pea-sized clumps. Set aside in the refrigerator.
  2. Sift the flour, sugar, baking powder, and salt into a large mixing bowl. Whisk thoroughly to ensure leavening agents are evenly distributed.
  3. In a separate bowl, whisk the egg, sour cream, milk, oil, and vanilla extract until the mixture is smooth and velvety.
  4. Pour the wet ingredients into the dry ingredients. Using a silicone spatula, gently fold the mixture together until just combined, leaving some streaks of flour. Gently fold in the flour-dusted blueberries.
  5. Divide the batter evenly among 12 lined muffin cups. Pile the chilled streusel generously on top of each muffin, pressing slightly.
  6. Bake at 400°F (205°C) for 5 minutes, then lower the heat to 350°F (175°C) and bake for another 15-20 minutes until a toothpick comes out clean.