I had this for lunch today - very nice with a tomato/onion salad with olive oil and balsamic vinegar dressing.
4 large eggs, separated
Salt and freshly ground black pepper
Half oz butter
3 oz Gruyere cheese
150g bag of ready washed baby spinach leaves
Place egg yolks in a large bowl and add nutmeg, salt and pepper. mix together
Whisk the egg whites until well set, but not dry then fold the egg whites into the egg yolks.
Melt the butter into a large frying pan, wait until the butter melts then swirl to ensure that the base and the sides are well coated. When the foaming subsides, add the egg mixture.
When the omelette is beginning to set, sprinkle over the grated cheese nad spinach. Cook until the omelette is lightly set. Fold in half and slide onto a warmed dish.