Sift the flour, baking powder and salt into a bowl. Stir in the sugar and make a well in the centre. Whisk together the milk, melted butter, egg and vanilla extract in a jug, then gradually whisk into the flour to form a smooth batter.
Heat a little of the butter for frying in a large frying pan over a medium heat. Add heaped tablespoons of the batter mixture to make pancakes about 8–10 cm (3 1/2–4 inches) in diameter.
Scatter the blueberries over the top of the batter and cook for 2–3 minutes until bubbles start to appear on the surface, then flip over and cook for a further 1–2 minutes. Remove from the pan and keep warm. Repeat with the remaining batter to make 8–10 pancakes, adding a little more butter to the pan and reducing the heat if necessary.
Serve the pancakes drizzled with maple syrup or honey, with a scoop of ice cream on top.