Bring a saucepan of salted water to the boil and add the pasta. Cook according to the pack instructions.
While the pasta are getting ready, heat a sauté pan and fry the chorizo pieces and the onion for 2-3 minutes until crispy.
In a separate bowl, beat together the egg yolks and half of parmesan cheese. Season lightly with cracked black pepper.
Add 2-3 tbsp of the cooking liquid of the pasta to loosen the mixture.
Once the pasta is cooked, drain it and return it to its saucepan.
Add in the chorizo mixture pieces and the egg and cheese mixture. Stir (off the heat) to coat the pasta with the egg and cheese mixture and allow the eggs to set with the residual of heat from the pasta. Season well with salt and pepper.
Transfer to the serving plates and sprinkle the rest of the parmesan and if desired extra fresh herb dressing.