Add egg whites to a large mixing bowl. Beat at high speed until stiff peaks form.
In a separate large bowl, whisk egg yolks, salt and pepper.
Add half of the egg whites into the egg yolk bowl. Sprinkle in 2 tbsp of cheese. Using a spatula, gently fold the egg whites in until they are incorporated into the egg yolks. Your mixture should look light yellow and fluffy. (See photo in post for reference.)
Add butter to a 10-inch nonstick skillet and bring to medium heat. Once butter is melted, move it around the skillet until the skillet surface is coated in butter.
While skillet is heating up, add in remaining egg whites to your egg yolk mixture. Gently fold in until egg whites are mostly incorporated. This should be done quickly and shouldn't take long. It's okay to have a few small lumps of egg whites.
Pour batter into the heated skillet. Use spatula to spread the batter evenly across the surface of the skillet. Cover skillet with a lid.
Cook until the bottom of the omelette has turned a light golden brown and surface of the egg is just set. Sprinkle remaining cheese on top and chives. Cover with lid and cook an additional minute or until cheese is melted.
Carefully slide egg onto a plate. Use a spatula to fold omelette in half. If desired, garnish with more chives before serving.
Make sure to beat eggs to stiff peaks. Medium or soft peaks are not enough.
You only have a small amount of time after your egg whites are incorporated to cook the omelette, otherwise the egg yolks will start to separate from the egg whites.
Make sure to keep the skillet covered when cooking otherwise the omelette will not cook through.
I recommend using a nonstick skillet.
You can mix up the cheese and herbs. I've also made this with gouda and parmesan.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.