Ingredients:

  • 100g light brown sugar, packed
  • 30g all-purpose flour
  • 1 tbsp ground cinnamon
  • 56g unsalted butter, melted and cooled
  • 250g all-purpose flour
  • 150g granulated sugar
  • 2 tsp baking powder
  • 1/2 tsp baking soda
  • 1/2 tsp fine sea salt
  • 1 tbsp ground cinnamon
  • 240g full-fat sour cream, room temperature
  • 2 large eggs, room temperature
  • 115g unsalted butter, melted and slightly cooled
  • 2 tsp pure vanilla extract

Instructions:

  1. In a small bowl, combine 100g brown sugar, 30g flour, and 1 tbsp cinnamon. Stir in 56g melted butter with a fork until it resembles wet sand with pea-sized clumps. Set aside.
  2. In a large mixing bowl, whisk together 250g flour, 150g granulated sugar, baking powder, baking soda, salt, and 1 tbsp cinnamon.
  3. In a separate vessel, whisk together the sour cream, eggs, 115g melted butter, and vanilla extract until smooth.
  4. Gently fold the wet ingredients into the dry ingredients using a spatula until just combined. Do not overmix.
  5. Allow the batter to rest at room temperature for 15 minutes to hydrate the flour. Meanwhile, preheat the oven to 425°F (218°C) and line a muffin tin.
  6. Divide the batter into 12 muffin cups and top generously with the prepared cinnamon streusel.
  7. Bake at 425°F for 5 minutes, then reduce the heat to 350°F (177°C) and bake for an additional 13-15 minutes until a toothpick comes out clean.