Do not overbeat the eggs; simply blend the yolks and whites after whisking in the salt, pepper, and water.
A nonstick pan should be heated on high. Move the pan around to coat with the butter after adding it; it should start to sizzle right away. Add the eggs once the butter has completely melted and any boiling or foaming has died down.
The eggs should immediately start to bubble. After letting them sit for about 5 seconds, stir the pan in a circular motion while maintaining contact with the heat. Continue swirling for approximately 3 seconds, or until the eggs start to coagulate into a flat circle that lifts off the pan.
When the omelet folds over on itself and reduces to approximately a third of its initial diameter, jerk the pan a couple times in your direction.
Holding the handle with your dominant hand with your palm up and your thumb facing out, rotate the pan 90 degrees. To fold the omelet onto a plate with the smooth bottom side facing up, flip the pan over (with the edge of the pan contacting the plate). If desired, add more butter and add parsley as a garnish. Serve right away.