Sift the flour, baking powder and caster sugar into a large bowl.
Make a well in the centre and quickly stir in the egg yolk, milk, lemon zest and melted butter with a wooden spoon.
Whisk the egg white until it forms stiff peaks and quickly fold into the mixture.
Heat and lightly grease a griddle pan (or frying pan if you don’t have one).
The pan is the right temperature when a drop of water splutters on the surface.
Using a small ladle or batter dispenser drop enough batter onto the griddle to form pancakes of about 7cm (3 in) in size.
Sprinkle a few raisins/currants onto the wet batter. Making 3 at a time works well.
Cook until bubbles form on the surface and they look slightly dry, turn and cook the other side until golden brown.
When cooked, either serve immediately, keep warm on a plate covered with foil over a pan of simmering water or serve cold.
Top with butter, jam, honey, syrup or lemon curd.
Should make 12 pancakes depending on size.