Ingredients:

  • 2 cups all-purpose flour (250g)
  • 3/4 cup granulated sugar (150g)
  • 2 tsp baking powder (10g)
  • 1 1/2 tsp ground cinnamon (4g)
  • 1/2 tsp salt (3g)
  • 1 large egg (50g)
  • 1/2 cup sour cream or Greek yogurt (120g)
  • 1/2 cup milk (120ml)
  • 1/2 cup melted unsalted butter (115g)
  • 1 tsp vanilla extract (5ml)
  • 2 medium Granny Smith apples, peeled and diced (300g)
  • 1/4 cup all-purpose flour (30g)
  • 1/4 cup brown sugar (50g)
  • 1/2 tsp ground cinnamon (2g)
  • 2 tbsp cold butter, cubed (28g)

Instructions:

  1. Preheat oven to 425°F (218°C) and line a 12-cup standard muffin tin with paper liners.
  2. Dice apples into small, uniform cubes. Toss them in a bowl with a pinch of cinnamon and 1 tablespoon of the measured flour to prevent sinking.
  3. In a small bowl, rub cold butter into 1/4 cup flour, brown sugar, and cinnamon using fingertips until a crumbly, pebble-like texture forms; set aside.
  4. In a large bowl, whisk together the 2 cups flour, granulated sugar, baking powder, cinnamon, and salt.
  5. Create a well in the center of the dry ingredients and add the egg, sour cream, milk, melted butter, and vanilla.
  6. Stir with a spatula until just combined; do not overmix.
  7. Gently fold in the flour-coated apple chunks.
  8. Divide the batter evenly among the 12 muffin cups, filling them about 3/4 full.
  9. Generously sprinkle the cinnamon streusel over each muffin, pressing lightly into the batter.
  10. Bake at 425°F (218°C) for the first 5 minutes to create high-domed tops, then continue baking until set.