In a large frying pan, heat olive oil until hot. Add leeks and saute them for 6-8 minutes, until soft. Lower heat and add chorizo. Fry over very low heat, turning occasionally until crisp.
Cook the pasta in a large saucepan of salted boiling water until al dente.
Meanwhile, crack the eggs into a bowl, add the Parmesan cheese and paprika, season well with salt and black pepper. Mix together with a fork.
Just before the pasta is ready, increase the heat under the drying pan so that the oil and melted fat start to sizzle. Drain the pasta thoroughly, return to the pan and immediately stir in the egg mixture and the sizzling hot contents of the frying pan.
Stir vigorously so that the eggs cook evenly. Serve immediately with a scattering of grated Parmesan cheese.