An omelette is a cooked egg dish made from eggs that are beaten, then poured into a frying pan, cooked to form a thin “pie”, then folded in half to form one of two classic folds, either the half-moon shape or the letter fold.
The Science of Good Food describes them as “soft scrambled eggs given shape by a thin skin of overcooked egg.” Joachim, David, Andrew Schloss and A. Philip Handel. The Science of Good Food. Toronto, Canada: Robert Rose. 2008. Page 204.
Often a filling is put on them before being folded. The type of filling can determine whether it is a breakfast, lunch or dinner dish.
Omelettes are almost always served hot.
For this reason, they are usually cooked for one person at a time. Some can be made big enough for two people, but after that they get unwieldy to manipulate in the pan:
“The trick is to have the right amount of egg for the size of the pan (3 eggs in a 10 inch/25 cm skillet) and a well–seasoned or nonstick pan to keep the egg moving freely.” Joachim, David, Andrew Schloss and A. Philip Handel. The Science of Good Food. Toronto, Canada: Robert Rose. 2008. Page 204.
Some cooks advise to not try to make omelettes for a crowd; it’s not worth the stress, they say, unless you are a trained cook.
There are special pans that are meant to make cooking omelettes easier, though many people have the knack of making them in plain old cast iron pans (usually the same people who could cook perfect fluffy rice in a tin can over a campfire.)
As a general rule, allow 3 eggs per omelette. You can reduce that to 2 eggs for light eaters, or for meals where there will be other stuff on the plate.
Adding salt to the eggs can toughen them; salt them at the table instead.
Water makes lighter omelettes than milk.
If a filling for the omelette is to be used, it needs to be the first thing you do before you start the omelette. The filling should be ready to go and either at room temperature or warm before you start cooking the eggs.
Swish the pan around so that runny uncooked egg will move to the sides of the pan where it can cook faster. You are ready to fold when the egg mixture is still just a bit wet on the top (but first, spread any filling or cheese on top before folding). You can do the classic half-moon fold, or the “letter” fold — one-third on one side over to the middle, then one-third on the other side over to the middle on top of the previous fold. (The letter fold is meant to be served upside down). After folding, you can remove it right away from the pan if you like omelettes soft, or let cook for a little bit longer if you like your omelette drier and firmer.
The total cooking time for the egg mixture should be no more than 3 minutes, which gives a very firm omelette; 2 minutes for a soft one.
Literature and lore
Harold McGee covered the question of how much liquid to add to omelettes in his book, “The Science and Lore of the Kitchen”.
“Scrambled eggs and omelets are both made by mixing the yolks and whites together – quite thoroughly in the case of omelets – and sometimes adding milk or water to produce a moister, somewhat softer mass; the coagulated proteins can hold somewhat more liquid than they do in the plain egg. The amount of liquid added is fairly critical. If so much is used that the holding capacity of the proteins is reached or exceeded then even the slightest overheating will cause the liquid to be squeezed out and form a separate puddle. For scrambled eggs, the recommended amount is between 2 and 5 teaspoons per egg, while the omelet, which is cooked more rapidly, will only hold 2 or 3. Many cooks add no liquid at all to either dish but take great care that the eggs do not dry out… Ordinary, or French omelets, are cooked over high heat in a thin, intact sheet which is turned onto itself while the upper surface is still partly liquid. “Puffy” omelets are actually stovetop versions of the soufflé. Omelets have been known in England since about 1600, and in France centuries before that. The word has gone through various forms – Alemette, homelaicte, omelette (the standard French) – and drives ultimately from the Latin lamela, ‘thin plate’.”  McGee, Harold. On Food & Cooking: The Science and Lore of the Kitchen. New York: Simon & Schuster, 1997. Page 70-71.
From the French word, Omelette. From there, things get strange.
Linguists speculate that the word came from “alumette”, a sword blade, referring to the omelette’s flat shape. Omelette’s weren’t always half-moon or letter-shaped, though. There are pictures of omelette’s made by historical food re-creationists who have made them long and flat, which might make the word’s origin make more sense.
|↑1||Joachim, David, Andrew Schloss and A. Philip Handel. The Science of Good Food. Toronto, Canada: Robert Rose. 2008. Page 204.|
|↑2||Joachim, David, Andrew Schloss and A. Philip Handel. The Science of Good Food. Toronto, Canada: Robert Rose. 2008. Page 204.|
|↑3||McGee, Harold. On Food & Cooking: The Science and Lore of the Kitchen. New York: Simon & Schuster, 1997. Page 70-71.|