Sift the flour into a large bowl. Beat the eggs together with the salt.
Make a well in the centre of the flour and pour in the eggs. With a wooden spoon, gently stir the flour into the eggs until incorporated.
Pour in the milk, a little bit at a time, and beat with each addition to create a smooth mixture. Continue until all the milk is added. Pour in the spoonful of oil and beat again. Cover the bowl with cling film and rest in the fridge for at least one hour.
Check the batter – if it seems thick, add a little water to loosen. It needs to be thicker than normal crêpe batter, approximately the consistency of Heinz tomato soup.
Set a non-stick frying pan over medium high heat. Pour a little flavourless oil onto some kitchen paper and brush it around the pan. Bring the pan to temperature, then, with one hand, pour in a ladleful of batter and with the other, swirl the frying pan, spreading the mixture to the edges.
Cook for 30 seconds to 1 minute. Check the underside – if there are patches of chocolate brown it is ready to flip. As the new side cooks, quickly crack in an egg on one half of the surface. Using a fork, break up the thicker white so it cooks quickly. As it cooks, add your favourite toppings such as ham, mushrooms, fried potatoes, or cooked onions, and finally some cheese. Close the galette and slide it onto a plate.