Beat the eggs and seasonings in the mixing bowl for 20 to 30 seconds until the whites and yolks are just blended.
Place the butter in the pan and set over very high heat. If you have an electric heat element, it should be red hot. As the butter melts, tilt the pan in all directions to film the sides. When you see that the foam has almost subsided in the pan and the butter is on the point of coloring, it is an indication that it is hot enough to pour in the eggs.
Hold the panhandle with your left hand, thumb on top, and immediately start sliding the pan back and forth rapidly over the heat. At the same time, fork in right hand, its flat side against the bottom of the pan, stir the eggs quickly to spread them continuously all over the bottom of the pan as they thicken. In 3 or 4 seconds they will become a light, broken custard. (A filling would go in at this point.)
Then lift the handle of the pan to tilt it at a 45-degree angle over the heat, and rapidly gather the eggs at the far lip of the pan with the back of your fork. Still holding the pan tilted over the heat, run your fork around the lip of the pan under the far edge of the omelette to be sure it has not adhered to the pan.
Give 4 or 5 short, sharp blows on the handle of the pan with your right fist to loosen the omelette and make the far edge curl over onto itself.
Hold the pan tilted over heat for 1 or 2 seconds to brown the bottom of the omelette very lightly, but not too long or the eggs will overcook. The center of the omelette should remain soft and creamy.
Turn the omelette onto the plate as illustrated on this page, rub the top with a bit of butter, and serve as soon as possible.