Preheat the oven to 220C/425F/Gas 7 (200C fan).
Measure the flour and salt into a bowl and make a well in the centre. Add the eggs and a little milk. Whisk until smooth and gradually add the remaining milk. This can be done with a wooden spoon, but is easier with an electric hand-held whisk. Pour the mixture into a jug.
Measure a dessertspoonful of oil into each hole of the 12 bun tray, or a tablespoonful in each hole of the four hole tins, or three tablespoonfuls into the roasting tin. Transfer to the preheated oven for five minutes, or until the oil is piping hot.
Carefully remove from the oven and pour the batter equally between the holes or the tin.
Return the batter quickly to the oven and cook for 20-25 minutes (35 if making the Yorkshire pudding in the roasting tin), or until golden-brown and well-risen. Serve immediately.