Sourdough Blueberry Muffins

Step 1
Preheat the oven to 375 degrees F (190 degrees C). Line 10 muffin cups with paper liners.

Step 2
Combine blueberries and 2 teaspoons flour and toss to coat.

Step 3
Combine 1 cup flour, baking soda, cinnamon, and salt in a bowl. Whisk sourdough starter, sugar, egg, melted butter, and vanilla extract together in a second bowl. Whisk briskly until no streaks appear. Mix flour mixture with sourdough mixture, and stir well. The batter will be quite thick. Fold blueberries into the batter.

Step 4
Spoon batter evenly into the prepared muffin cups.

Step 5
Combine sugar, flour, butter, and cinnamon for the topping in a bowl and mix with a fork until crumbly. Sprinkle topping over the muffins.

Step 6
Bake in the preheated oven until tops spring back when lightly pressed and a toothpick comes out clean, 20 to 22 minutes. Cool in the pan for 10 minutes. Transfer to a wire rack to cool completely.