Double Streusel Blueberry Muffins
Ingredients
For the streusel topping
  • ½ cup all-purpose flour
  • ½ cup granulated sugar
  • ¼ teaspoon ground cinnamon
  • 4 tablespoons cold unsalted butter, cubed
For the muffins
  • 4 tablespoons unsalted butter, at room temperature
  • ½ cup granulated sugar
  • ½ teaspoon vanilla extract
  • 1 large egg, at room temperature
  • 1 cup all-purpose flour
  • ½ teaspoon baking powder
  • ¼ teaspoon baking soda
  • ½ cup sour cream
  • 1 cup fresh blueberries, picked through for stems
Instructions
For the streusel topping
  • In a small bowl, whisk together the flour, sugar, and cinnamon. Add the butter. Using your fingers or a pastry cutter, work the butter into the dry ingredients until the mixture resembles coarse crumbs. Set aside.
  • For the muffins
    • Heat oven to 350 degrees F. Place 6 paper muffin molds on a rimmed baking sheet.
    • In the bowl of an electric mixer fitted with the paddle attachment, cream the butter, sugar, and vanilla together until light and fluffy, about 5 minutes, scraping down the sides of the bowl about half way through. Add the egg and blend until combined. In a separate bowl, whisk together the flour, baking powder, and baking soda. Add half of the sour cream to the butter-sugar mixture and mix until combined. Then add half of the dry ingredients and mix again. Repeat with the remaining sour cream and dry ingredients until the batter is combined. Fold in the blueberries with a spatula until the batter is evenly mixed.
    • Scoop the batter into the muffin molds, filling each cup about halfway. Top each muffin with streusel topping evenly dividing the topping among the muffins. Bake for 25 to 30 minutes, until the muffins are lightly browned on top and a cake tester comes out clean.
    • Cool muffins for 10 minutes before serving.
Notes
For the streusel topping, you can also use a food processor to cut the butter into the dry ingredients. I find that the food processor can make the crumbs too fine so be careful not to over-pulse as you want some larger pieces of crumbs.

I use paper muffin molds that are 2¾ inches in diameter x 2 inches high.

Recipe adapted from the Clinton St. Baking Company cookbook.
Recipe by Taming of the Spoon at http://tamingofthespoon.com/double-streusel-blueberry-muffins/