Ingredients:

  • 125g all-purpose flour
  • 100g packed brown sugar
  • 50g granulated sugar
  • 1 tbsp ground cinnamon
  • 115g cold unsalted butter, cubed
  • 250g all-purpose flour
  • 2 tsp baking powder
  • 0.5 tsp baking soda
  • 0.5 tsp sea salt
  • 115g unsalted butter, melted and cooled
  • 150g granulated sugar
  • 2 large eggs, room temperature
  • 240g full-fat sour cream
  • 1 tbsp vanilla extract
  • 120g powdered sugar
  • 2.5 tbsp whole milk
  • 1 tsp vanilla bean paste

Instructions:

  1. Preheat oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners.
  2. Prepare the streusel by whisking 125g flour, 100g brown sugar, 50g granulated sugar, and 1 tbsp cinnamon in a medium bowl. Use a pastry cutter to cut in 115g cold, cubed butter until pea-sized clumps form. Refrigerate until needed.
  3. In a large mixing bowl, whisk together 115g melted butter and 150g granulated sugar. Add the 2 large eggs one at a time, followed by 240g sour cream and 1 tbsp vanilla extract. Whisk vigorously until emulsified and glossy.
  4. Sift 250g flour, baking powder, baking soda, and sea salt directly over the wet ingredients. Fold gently with a rubber spatula until just combined; do not over-mix.
  5. Layer the muffins by placing a small spoonful of batter into each tin, followed by a sprinkle of streusel. Top with remaining batter and a heavy layer of the remaining streusel.
  6. Bake for 22 minutes or until a toothpick inserted into the center comes out clean. Transfer to a wire rack to cool.
  7. Whisk 120g powdered sugar, 2.5 tbsp milk, and 1 tsp vanilla paste to create the glaze. Drizzle over the muffins once they have cooled slightly.