Cut the chorizo into 4 pieces for every round, as shown in the photo.
Over medium-high heat cook the chorizo and dice the onion or shallots.
After a few minutes you should have enough oil from the chorizo to fry the onion or shallots in.
Remove the chorizo leaving the oil in the pan. Turn the heat down to low-medium and cook the onion/shallots until they are soft and take on good colour from the chorizo oil. If the pan starts to dry out just add some olive oil.
If you’re having tortillas, cook or warm them now, and keep them warm.
In a saucepan over medium heat, add the butter and eggs.
Stir constantly with a spatula until you start to see little lumps of cooked eggs form. Remove from the heat occasionally so that the eggs don’t overcook.
As the eggs are cooking combine the chorizo and the onion/shallots and keep warm.
When the eggs are almost done, stir in a dollop of cream (or sour cream) to help stop the cooking process and then add the chorizo and the onion/shallots. Taste for seasoning.
Serve on warmed plates, add the cheese, and jazz up with some coriander (cilantro) or some sliced eschallots.
You can turn these into burritos (see the photo) which are great as finger food if you have a lot of guests.