Heat a nonstick skillet over medium heat for 2–3 minutes.
In a bowl, whisk egg whites with salt, pepper, and garlic powder until frothy.
Lightly spray the skillet with olive oil.
Pour in the egg whites, tilting the pan to spread evenly.
Add cherry tomatoes and scallions on top.
Once edges begin to set, reduce heat to medium-low.
Gently lift edges and tilt the pan to allow uncooked egg to flow underneath.
When nearly set, carefully flip the omelette.
Sprinkle Parmesan cheese on top.
Fold the omelette and transfer to a plate.
This Egg White Omelette is best enjoyed immediately while warm and fluffy.