How to Make Blueberry Bread:
Begin by preheating your oven to 350°F. Prepare a 6-cup bread loaf pan (measuring 8 1/2 by 4 1/2 inches) by buttering it generously, then dusting it with flour and tapping out any excess.
In a medium-sized mixing bowl, whisk together the flour, baking powder, and salt, then set this mixture aside.
In a separate large mixing bowl, cream the softened butter and half of the granulated sugar together on medium to high speed until the mixture is well combined. Gradually add the remaining sugar and continue beating for an additional two minutes. Incorporate the eggs, vanilla extract, and 1 teaspoon of lemon zest, mixing until fully integrated.
Next, gradually add the flour mixture in two portions, alternating with the milk. Mix on medium to low speed, ensuring you incorporate each addition just until combined. Use a spatula to scrape down the sides of the bowl as necessary.
In a small bowl, toss the blueberries with 1/2 tablespoon of flour, then gently fold them into the batter, taking care not to overmix. Transfer the batter into the prepared loaf pan and bake for 50 to 60 minutes, or until the top is golden and a toothpick inserted into the center comes out clean. Allow the bread to cool in the pan for 10 to 15 minutes before running a cake release tool or knife around the edges, then transfer the loaf to a wire rack to cool completely before glazing.
To Make the Lemon Glaze:
Once the bread has cooled entirely, prepare the glaze by combining the powdered sugar, lemon juice, and the reserved 1/2 teaspoon of lemon zest in a separate bowl. Stir until the mixture is smooth and reaches a drizzling consistency. Adjust the thickness by adding more lemon juice to thin it out or more powdered sugar for a thicker glaze.