First of all sift the flour and salt into a large mixing bowl with the sieve held high above the bowl so the flour gets an airing.
Now make a well in the centre of the flour and break the eggs into it. Then begin whisking the eggs using an electric whisk or a balloon whisk – incorporating any bits of flour from around the edge of the bowl as you do so.
When the mixture starts thicken, gradually add small quantities of the milk and water mixture, still whisking (don't worry about any lumps as they will eventually disappear as you whisk).
When all the liquid has been added, use a rubber spatula to scrape any elusive bits of flour from around the edge into the centre, then whisk once more until the batter is smooth, with the consistency of thin cream.
Now melt the butter in the pan. Spoon 2 tablespoons of it into the batter and whisk it in, then pour the rest into a bowl and use it when needed to lubricate the pan, using a wodge of kitchen paper to smear it round.
Now get the pan really hot, then turn the heat down to medium and, to start with, do a test pancake to see if you're using the correct amount of batter. I find 1¾ tablespoons (35mls) about right for the Delia Online Frying Pan.
It's also helpful if you spoon the batter into a ladle or a small coffee cup so it can be poured into the hot pan in one go. Hold the ladle so that the base is very close to the bottom of the pan then pour in.
As soon as the batter hits the hot pan, tip it around from side to side to get the base evenly coated with batter. If you have any holes in it, add a teaspoon of the mixture just to fill them in. It should take only half a minute or so to cook; you can lift the edge with a palette knife to see if it's tinged gold as it should be.
Flip the pancake over with a pan slice or palette knife – the other side will need a few seconds only – then simply slide it out of the pan on to a plate.
Overlap the pancakes as you go on a plate fitted over simmering water, to keep them warm while you make the rest. (Or if you are freezing them stack them with a piece of baking parchment between them and pop them in a freezer bag).
To serve, sprinkle each pancake with caster sugar and freshly squeezed lemon juice, fold in half, then in half again to form triangles, or else simply roll them up.
Serve sprinkled with a little more sugar and lemon juice and some lemon wedges.