Wash the spinach and cook in a pan with a little olive oil. Salt, pepper and chop coarsely with the knife.
In a bowl beat with the help of a blender eggs, with milk, a pinch of salt and pepper and parmesan cheese. Mount well so that they are filled with air.
Add the chopped spinach and pour the mixture into a baking dish covered with oven paper.
Bake the omelette in a preheated oven at 180ºC for about 25 minutes.