Heat pan to medium low, add tsp oil, brush to coat pan
Add spinach to pan, cover about 1-2 minutes
In a measuring cup, crack 1 egg, fill rest with egg whites to 1 cup line, pour over spinach. If you opted to use nutritional yeast, sprinkle on top, cover.
Once egg whites have cooked (not clear or moving like jell-o), use spatula to flip, cooking the top for no more than 10-20 seconds
Fold omelette in half, serve.