2 cups all-purpose flour

1 teaspoon baking powder

1 teaspoon baking soda

1/2 teaspoon salt

1/2 cup unsalted butter, softened

1 cup granulated sugar

2 large eggs

1 teaspoon pure vanilla extract

1 cup sour cream

1 1/2 cups fresh or frozen blueberries (if using frozen, do not thaw)

FOR THE STREUSEL TOPPING:

1/2 cup granulated sugar

1/2 cup all-purpose flour

1/4 cup unsalted butter, chilled and cubed

1 teaspoon ground cinnamon

FOR THE GLAZE (OPTIONAL):

1/2 cup powdered sugar

2-3 tablespoons milk

1/2 teaspoon pure vanilla extract

2 cups all-purpose flour

1 teaspoon baking powder

1 teaspoon baking soda

1/2 teaspoon salt

1/2 cup unsalted butter, softened

1 cup granulated sugar

2 large eggs

1 teaspoon pure vanilla extract

1 cup sour cream

1 1/2 cups fresh or frozen blueberries (if using frozen, do not thaw)

FOR THE STREUSEL TOPPING:

1/2 cup granulated sugar

1/2 cup all-purpose flour

1/4 cup unsalted butter, chilled and cubed

1 teaspoon ground cinnamon

FOR THE GLAZE (OPTIONAL):

1/2 cup powdered sugar

2-3 tablespoons milk

1/2 teaspoon pure vanilla extract