Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper. Place the flour, baking powder, sugar, and salt in a bowl and whisk to combine. Cut in the butter until the mixture is a pea-sized crumble. Add the milk and blueberries and very gently stir until the dough just holds together. Transfer the dough to a lightly floured surface and very gently shape into a ball. Gently press the dough into a circle that is about 1 inch thick. With a 3 inch round cookie cutter, cut the dough into 10 to 12 rounds and place on the baking sheet. Brush the tops of the scones with the melted butter. Bake for 18 to 20 minutes, or until puffed and golden. If desired, broil the tops of the scones for a few seconds to enrich their colour.