This section is from the book "The American Woman's Cook Book", by Ruth Berolzheimer. Also available from Amazon: The Domestic Arts Edition of the American Woman's Cook Book.
Variations of the plain puffy omelet or the plain French omelet may be made by adding any of the following ingredients to the omelet before it is put into the pan to cook, or by spreading one of them on top just before the omelet is folded. Allow one tablespoon of mixture to each two eggs used.
Ham or Other Meat - Scatter minced cooked meat over the center of the omelet while it is cooking. The meat may be browned in a small amount of fat before it is added.
Jardiniere - Stir into the beaten eggs, before cooking, a mixture of chopped parsley, onion, chives, shallots, and a few leaves each of sorrel and chervil, minced.
Jelly - Spread any jelly or jam over the omelet just before folding.
Onion - Mix one tablespoon chopped onion and one teaspoon chopped parsley. Add to the omelet mixture before cooking.
Parsley - Scatter minced parsley over the center of the omelet while it is cooking.
Vegetable - Use cooked left-over vegetables, one vegetable alone or two in combination. Mash the vegetable through a sieve, moisten with a little milk, cream or gravy, and season with salt and pepper. Lightly spread the mixture over the omelet before folding.