To ensure your omelets turn out just right, use a nonstick skillet to make the job easier.
Whisk together the eggs, water, and salt. Heat a well-seasoned (or nonstick) 8-inch skillet over high heat, about 30 seconds.
Add the butter. It should bubble but not smoke or burn. (If it does burn, wipe out the butter and start over.) Swirl the butter around the pan and immediately pour in the eggs. When the eggs begin to turn opaque around the edges, use a heatproof plastic spatula to pull the cooked eggs away from the sides of the pan. Swirl the pan to fill in the opening with the uncooked eggs. Reduce the heat to medium low. Repeat swirling until the omelet's underside is set all around and the top is still slightly undercooked.
Fold in one third of the omelet over, away from the handle side of the pan. Using a spatula, loosen the bottom of the omelet. Holding the pan with your palm under the handle, slide the unfolded edge onto a plate. As it slides off the edge of the pan, use the edge of the pan to help flip the 2/3 folded portion over the unfolded 1/3 portion on the plate. You'll form a roll with the seam on the bottom side. Garnish with chopped fresh herbs and serve immediately.