Mix the flour and salt together in a large bowl.
Make a well in the centre and crack in the eggs.
In a separate bowl mix together the milk and the water.
Beat the eggs into the flour with a wooden spoon and gradually beat in the milk and water mixture to get a smooth liquid the consistency of single cream.
Stir in the oil and allow to stand for 30 minutes before using.
Heat a non-stick frying pan until very hot, then add a small knob of butter. Ladle in a ladleful of the batter, quickly turning the pan to coat the base evenly with the batter. Cook for 30 seconds to one minute, until the base is lightly browned.
Using a palette knife, gently flip the pancake over and cook on the other side for a few seconds, until lightly browned. Slide the pancake onto a plate, cover with greaseproof paper and keep warm. Repeat the process with the remaining batter.
To serve, sprinkle the pancakes with caster sugar and lemon juice, then fold twice to form triangles. Serve the lemon wedges alongside.