Heat a 7-inch skillet over medium-high heat, add the butter, and when it stops foaming, tilt the pan to coat evenly. Add the eggs all at once. Shake the pan, slip a thin spatula under the eggs just as soon as they are set, and lift the eggs, tilting the pan to let the uncooked portion flow underneath. Fill, if desired, then roll over one-third of the omelette and tilt it onto a warm plate, making another fold.

Fillings:

    •   Shredded Monterey Jack cheese and chopped green chilies

    •   Mixed minced fresh herbs such as tarragon, flat-leaf parsley, chives, basil, and marjoram

    •   Feta cheese and minced fresh dill

    •   Goat cheese and minced fresh chives or tarragon

    •   Caviar, sour cream, and chopped red onion or minced fresh chives

    •   Smoked salmon, sour cream, and minced fresh chives or chopped green onions

    •   Sautéed white or brown mushrooms, shallots, and goat cheese

    •   Crabmeat, bay scallops, or bay shrimp heated in butter, and minced fresh dill, cilantro,
        or chives

    •   Shredded Gruyère cheese and minced fresh chives

    •   Cooked asparagus tips, broccoli florets, or artichoke hearts, and Parmesan cheese

    •   Sautéed chopped spinach and chopped green onions

    •   Sliced avocado, mango chutney, and shredded Jarlsberg or Monterey Jack cheese

    •   Sautéed chopped red and yellow bell peppers, red onions, and minced fresh basil

    •   Ratatouille, shredded Gruyère, and minced fresh basil