Ingredients:

  • 1/2 cup (65g) all-purpose flour
  • 1/2 cup (100g) granulated sugar
  • 1 tsp (2g) ground cinnamon
  • 4 tbsp (56g) cold unsalted butter, cubed
  • 2 cups (250g) all-purpose flour
  • 3/4 cup (150g) granulated sugar
  • 2 tsp (10g) baking powder
  • 1/2 tsp (3g) salt
  • 2 large eggs, room temperature
  • 1/2 cup (120g) sour cream
  • 1/2 cup (115g) unsalted butter, melted and cooled
  • 1/2 cup (120ml) whole milk
  • 1 tsp (5ml) vanilla extract
  • 1 1/2 cups (225g) fresh blueberries
  • 1 tbsp all-purpose flour (for tossing berries)

Instructions:

  1. In a medium bowl, whisk together 65g flour, 100g sugar, and 2g cinnamon.
  2. Use a pastry cutter or fingertips to work the cold, cubed butter (56g) into the mixture until it resembles coarse wet sand with pea-sized lumps. Set aside in the refrigerator.
  3. Preheat oven to 425°F (218°C). Grease a muffin tin or line with paper liners.
  4. In a large bowl, whisk together 250g flour, 150g sugar, 10g baking powder, and 3g salt.
  5. In a separate bowl, whisk together melted butter (115g), eggs, sour cream (120g), milk (120ml), and vanilla extract until smooth.
  6. Pour the wet ingredients into the dry ingredients and stir with a spatula until just combined; stop when a few streaks of flour remain.
  7. Gently fold in the blueberries (previously tossed in 1 tbsp flour) using a sweeping motion.
  8. Fill each muffin cup to the brim and top generously with the chilled streusel mixture.
  9. Bake at 425°F for 20 minutes or until the tops are golden and set.