Preheat the oven to 350°F. Grease an 8½x4½-inch loaf pan with butter or baking spray. (You can also line it with parchment paper.)
In a large mixing bowl, whisk together the flour, baking powder, and salt.
In a medium mixing bowl, whisk together the sugar, oil, melted and cooled butter, egg, and vanilla until smooth and lightened in color. Whisk in the milk until fully combined.
Place the blueberries in a medium mixing bowl. Sprinkle 2 teaspoons of the flour mixture over the blueberries. Gently toss to combine.
Pour the milk mixture into the remaining flour mixture and stir together with a spatula until almost fully combined and only a few streaks of dry flour remain. Gently but quickly fold the blueberry mixture into the batter. Pour into the prepared loaf pan.
Bake for 65 to 75 minutes or until a toothpick inserted into the center comes out with a few moist crumbs. Let the bread cool in the pan for 10 minutes then turn it onto a wire rack to cool completely.
