Sour Cream Blueberry Muffins

Preheat the oven to 400 degrees F (200 degrees C). Spray 16 muffin cups with cooking spray or line cups with paper liners.

Combine 1/2 cup flour, 1/4 cup brown sugar, 1/2 teaspoon cinnamon, and 1/4 teaspoon salt in a small bowl. Cut butter into the flour mixture until it is crumbly. Set crumb topping aside.

Whisk 2 cups flour, baking powder, 1 teaspoon cinnamon, and 1/4 teaspoon salt together in a large bowl, making a well in the center. Whisk eggs, granulated sugar, and 1/2 cup brown sugar together in a separate bowl. Stir in sour cream, vegetable oil, and vanilla extract until well combined. Pour into the well in the flour mixture and stir until batter is just combined without overmixing. Toss blueberries with 1 tablespoon flour in a small bowl and gently fold into the batter.

Spoon batter into the prepared muffin cups, filling each 3/4 full. Top each muffin with about 1 tablespoon of crumb mixture.

Bake in the preheated oven until tops spring back when lightly pressed and muffins are lightly browned, 18 to 22 minutes. A toothpick inserted into the center of the muffins should come out clean. Cool in the tins for 10 minutes. Transfer to a wire rack to cool completely.