Lightly whisk the eggs with a couple of pinches of salt.
Remove the skin of the chorizo and crumble the meat into a frying pan.
Heat the frying pan over medium heat, allowing the fat to release gently.
When the chorizo starts to brown, add the eggs, stir and let it spread out evenly.
Turn the heat down and put a lid on.
Meanwhile, slice the mozzarella.
After a couple of minutes, lay the mozzarella slice on the surface and cook for another 2 minutes or so until it starts melting and the surface of the egg has set.
Now scatter the spinach on top and put the lid on again to allow it to steam.
Gently fold over the omelette, let it sit for half a minute, then slide it onto a plate.
Cut in half and serve with a green salad.