Separate the egg whites into a clean bowl, making sure no yolk gets in. Add a pinch of salt.
Whisk vigorously with a fork or whisk for about 30 seconds until the whites become frothy and soft peaks form, feeling light and slightly opaque.
Heat a non-stick skillet over medium-low heat and add a teaspoon of butter or oil, swirling to coat evenly. You should see a gentle shimmer, not smoke.
Pour the whipped egg whites into the skillet, spreading them evenly. Let them sit undisturbed for about 15–20 seconds until the edges start to set and turn slightly golden.
Gently tilt the pan and use a silicone spatula to nudge the edges, encouraging the uncooked whites to flow outward. The surface should remain mostly moist but mostly set after about 1 minute.
Add the sautéed vegetables and cheese on one side of the omelette. Fold it carefully in half using the spatula, creating a tender, layered shape.
Cover the skillet loosely with a lid or foil, and cook for another 30–60 seconds until the cheese melts and the top is just set but still moist.
Gently slide the omelette onto a plate, letting it rest for a few seconds to settle and enhance its fluffy texture. Sprinkle with chopped herbs for freshness.
Serve immediately while the omelette is tender and light, enjoying the delicate layers and savory fillings.
