Preheat your oven to 350°F and generously grease a 9x5 inch loaf pan with butter or cooking spray.
In a medium bowl, whisk together the flour, baking powder, and salt until well combined, then gently fold in the blueberries to coat them in flour which helps prevent sinking.
In a large mixing bowl, cream together the softened butter and sugar with an electric mixer on medium speed for 2-3 minutes until light and fluffy.
Beat in the eggs one at a time until fully incorporated, then mix in the vanilla extract until the batter is smooth.
Alternately add the flour mixture and milk to the butter mixture, beginning and ending with flour, mixing on low speed just until combined without overmixing.
Pour the batter into the prepared loaf pan and spread it evenly with a spatula, then bake for 55-65 minutes until a toothpick inserted into the center comes out clean.
Let the loaf cool in the pan on a wire rack for 15 minutes before carefully turning it out onto the rack to cool completely for at least 1 hour before slicing.