Preheat your oven to 350°F (175°C). Grease a loaf pan.
In a mixing bowl, combine flour, sugar, baking powder, and salt.
In another bowl, whisk together melted butter, eggs, vanilla extract, milk, and lemon zest.
Pour the wet ingredients into the dry ingredients and mix until just combined.
Gently fold in the blueberries.
Pour the batter into the prepared loaf pan and bake for 60 minutes, or until a toothpick inserted into the center comes out clean.
Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.