Preheat the oven to 200°C/400°F/Gas mark 6. Grease a baking tray.
Sift the flour and salt into a bowl. Rub the butter into the flour, then add the sugar and baking powder. Whisk the egg and add the milk. Mix with the dry ingredients to form a stiffish dough. Divide the dough into 10 equal portions, and roll into balls.
Lay the balls of dough on the greased baking tray, and make a hole in the top of each using your thumb. Fill with a small quantity of raspberry jam, and pinch the dough together again. Flatten the buns slightly, brush with melted butter and dust with sugar. Bake for about 15 minutes until the tops of the buns crack open slightly to reveal the jam.