Mrs. S.T. Rorer, Many Ways for Cooking Eggs — Omelets (1907)
“ A plain French omelet is, perhaps, one of the most difficult of all things to make; that is, it is the most difficult to have well made in the ordinary private house. Failures come from beating the eggs until they are too light, or having the butter too hot, or cooking the omelet too long before serving.In large families, where it is necessary to use a dozen eggs, two omelets will be better than one. A six-egg omelet is quite easily handled. Do not use milk; it toughens the eggs and gives an unpleasant flavor to the omelet. ”
