Preheat the oven to 350°F (175°C). Grease and flour a 9×5-inch loaf pan or line it with parchment paper.

In a medium bowl, whisk together the flour, salt, and baking powder. Set aside.

In a separate large bowl, mix the melted butter and sugar until smooth. Add the eggs, one at a time, beating well after each addition. Stir in the lemon juice, lemon zest, and vanilla extract.

Gradually add the flour mixture to the wet ingredients, alternating with the milk, starting and ending with the flour mixture. Stir until just combined.

Gently fold in the blueberries. If using frozen blueberries, do not thaw them to prevent the batter from turning blue.

Pour the batter into the prepared loaf pan and spread it evenly.

Bake for 50-60 minutes, or until a toothpick inserted into the center of the loaf comes out clean. If the top is browning too quickly, cover it loosely with aluminum foil.

Let the loaf cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.

Prepare the lemon glaze: In a small bowl, whisk together the melted butter, powdered sugar, vanilla extract, and lemon juice until smooth.

Drizzle the lemon glaze over the cooled loaf before slicing and serving.