Ingredients:

  • 3 tablespoons All-Purpose Flour (for streusel)
  • 2 tablespoons Old-Fashioned Rolled Oats (for streusel)
  • 3 tablespoons Light Brown Sugar, packed (for streusel)
  • ½ teaspoon Ground Cinnamon (for streusel)
  • 2 tablespoons Unsalted Butter, cold, diced (for streusel)
  • 1 ½ cups All-Purpose Flour, spooned and levelled
  • ½ cup Old-Fashioned Rolled Oats
  • ¼ cup Granulated Sugar
  • ½ cup Light Brown Sugar, packed
  • 2 teaspoons Baking Powder
  • ½ teaspoon Baking Soda
  • 1 teaspoon Ground Cinnamon
  • ¼ teaspoon Ground Nutmeg
  • ½ teaspoon Fine Sea Salt
  • 2 Large Eggs, room temperature
  • ⅓ cup Unsalted Butter, melted and slightly cooled
  • ¾ cup Buttermilk (or whole milk with 1 tsp white vinegar)
  • 1 teaspoon Pure Vanilla Extract
  • 1 ½ cups Firm, Tart Apples, peeled and diced small

Instructions:

  1. Preheat the oven to 425°F (220°C). Line a 12-cup muffin tin with paper liners. Prepare the diced apples and set aside.
  2. To make the streusel: In a small bowl, combine flour, oats, brown sugar, and cinnamon. Cut in the cold, diced butter until the mixture resembles coarse crumbs. Place in the fridge.
  3. In a large mixing bowl, whisk together the flour, rolled oats, both sugars, baking powder, baking soda, cinnamon, nutmeg, and salt.
  4. In a separate, medium bowl, lightly whisk the two eggs until just combined. Whisk in the cooled melted butter, buttermilk, and vanilla extract until smooth.
  5. Pour the wet ingredients into the dry ingredients. Using a rubber spatula, fold the ingredients together gently until just combined. Gently fold in the diced apples until they are evenly distributed. Do not overmix.
  6. Divide the batter evenly among the 12 prepared muffin cups, filling them almost to the brim. Sprinkle a generous amount of the chilled streusel topping over the top of each muffin.
  7. Place the tin in the preheated 425°F (220°C) oven and bake for 5 minutes. Immediately reduce the oven temperature to 375°F (190°C) and continue baking for an additional 15–17 minutes, or until deep golden brown.
  8. Allow the muffins to cool in the tin for 5 minutes. Transfer them to a wire rack to cool completely, or serve warm.