Heat a drizzle of oil in a frying pan over medium heat. Add the chorizo and spring onion and cook and stir till browned. (Add some chopped garlic, if liked.)
Reserve a bit of the cheese to sprinkle on top of the muffins. Combine the eggs, cheese, parsley and chorizo mixture. Pour into a silicone muffin mould, or a muffin tin lined with paper cases. I also greased the mould lightly with olive oil as I absolutely hate my muffins getting stuck.
Bake for 20 minutes, or till a knife inserted in the centre of a muffin comes out clean.
These egg muffins come out the oven all puffed up and gorgeous, but tend to collapse a bit when cooling down. Don't let this deter you - they taste delish all the same.