Blueberry Streusel Coffee Cake Loaf

Ingredients

• ⅓ cup (76g) unsalted butter (at room temperature)
• ⅔ cup (121g) granulated sugar
• 1 larger egg (at room temperature)
• 1 teaspoon vanilla extract
• 1 ½ (184g) all-purpose flour
• ¾ teaspoon baking powder
• ½ teaspoon baking soda
• ¼ teaspoon salt
• ¼ cup (72g) sour cream (at room temperature)
• ¼ cup (72g) milk (at room temperature)
• 1 cup blueberries (fresh or frozen, coated in flour)
• ⅔ cup (74g) all-purpose flour
• ⅓ cup (74g) granulated sugar
• Pinch of salt
• 3 Tablespoons (43g) unsalted butter (softened and cut into pieces)
• ¼ teaspoon vanilla extract