Preparation Steps

• Preheat your oven to 375°F (190°C). Lightly grease an 8x8-inch or 9x9-inch square baking pan.
• Make the streusel topping: In a small bowl, whisk together 0.33 cup sugar, 0.5 cup flour, cinnamon, and 0.125 teaspoon salt. Cut in the cold, cubed butter using a pastry blender or your fingers until the mixture resembles coarse crumbs. Set aside.
• Make the cake batter: In a medium bowl, whisk together the 2 cups of flour, baking powder, and 0.5 teaspoon salt.
• In a large bowl, beat the softened butter and 0.75 cup sugar together until light and fluffy. Beat in the egg and vanilla extract until well combined.
• Gradually add the dry flour mixture to the wet ingredients, alternating with the milk, beginning and ending with the flour mixture. Mix until just combined. The batter will be thick.
• Gently fold the fresh blueberries into the batter.
• Spread the batter evenly into the prepared baking pan. Sprinkle the streusel topping evenly over the top of the batter.
• Bake for 40 to 45 minutes, or until a toothpick inserted into the center of the cake comes out clean.
• Remove from the oven and let the coffee cake cool in the pan for at least 10 minutes before slicing and serving.