In a medium bowl mix together the egg yolks and grated Parmesan. Set aside.
Bring a large pot of salted water to the boil. Add the pasta and cook until al dente. Drain, reserving a cupful of pasta water.
Meanwhile, heat the oil in a large pan over a medium heat. Add the chorizo and fry for 1 minute until they release their flavour. Add in the garlic and oregano and fry for a further 2 minutes, stirring often. Remove from the heat and set aside.
Add a splash of pasta water to the egg yolks and whisk to combine.
Once the pasta has cooked place the chorizo back on a medium heat. Add the pasta to the pan with the chorizo and stir until everything is heated through.
Remove from the heat and stir in the egg yolk mix adding splashes of pasta water until you have a creamy sauce. Place back over a low heat, if necessary, to thicken. Finally, stir through the fresh parsley and divide into bowls. Serve with a sprinkling of chilli flakes or a spoonful of chilli sauce and an extra grating of Parmesan.
