Melt the butter then leave to cool slightly. Place the flour in a bowl or jug and gradually whisk in the eggs and milk. Finally whisk in the cooled butter. You should end up with a smooth batter about the consistency of single cream. If you prefer you could use a blender instead.
Heat a pancake pan or non stick frying pan over a moderate heat. When the pan is hot add a little oil and carefully wipe it around the pan with a wad of kitchen roll. Add enough batter to thinly cover the base of the pan and swirl it around to make sure that it is covered evenly. Cook until the base is a pale golden brown colour and the top looks set.
Flip the pancake over, use a palette knife if you're not confident about tossing them. Cook until the second side has turned golden, this side will look slightly different from the first side with golden brown spots over the surface. Tip onto a plate and cover with tinfoil to keep warm then repeat the process with the rest of the batter. Keep re-oiling the pan when necessary. [Don't worry if the first pancake isn't right, the pan may not be quite hot enough or you may have misjudged the amount of batter needed - simply treat it as the cook's perk!]
Serve the pancakes with caster sugar and lemon or orange juice, grilled bacon and maple syrup or any other filling of your choice.