Preheat and prepare pan. Preheat oven to 350°F (177°C). Spray a 9x5” loaf pan with non-stick cooking spray or grease with butter and flour, or line with parchment paper and set aside.
Prepare topping. In a small mixing bowl, combine the brown sugar and cinnamon. Set aside. ½ cup (107 g) packed light brown sugar 1 tablespoon ground cinnamon
Combine dry ingredients. In a mixing bowl, whisk together flour, sugar, baking powder, and salt. 2 cups (240 g) all purpose flour ½ teaspoon salt 1 tablespoon baking powder 1 cup (200 g) granulated sugar
Combine wet ingredients. In a second mixing bowl, whisk together eggs, sour cream, melted butter, and vanilla extract. 2 large eggs ½ cup (1 stick, 113 g) unsalted butter melted ⅔ cup (151 g) sour cream 2 teaspoons vanilla extract
Combine wet and dry ingredients. Add the dry ingredients to the wet ingredients and mix together with a spatula until just combined. Fold in the blueberries. 1 ½ cups blueberries
Assemble bread. Pour ½ of the batter into prepared loaf pan. Sprinkle on ½ the cinnamon sugar topping.
Make streusel. With the remaining brown sugar cinnamon sugar mixture add the melted butter and flour. Stir until a crumbly mixture forms. 2 Tablespoons (28 g) unsalted butter 2 Tablespoons all purpose flour
Assemble rest of the bread. Add the remaining batter and spread on top. Sprinkle on the crumble topping.
Bake the bread. Bake for 60-70 minutes until a toothpick inserted in the center of the bread comes out clean. Remove from the oven and allow the bread to cool completely in the pan set on a wire cooling rack. Store the bread, and any leftovers, covered at room temperature for 2 days, or in the refrigerator for up to 1 week.
Make the glaze. Whisk together the glaze ingredients and drizzle over the cooled bread. 1 ½ cups (180 g) powdered sugar 2-3 tablespoons milk ½ teaspoon vanilla extract