Bring a large pot of water to a boil. Season with salt and cook pasta to al dente.
In a small saucepot, warm chicken stock with a few threads of saffron. Let steep for a while over low heat.
Heat a large skillet over medium-high heat with EVOO, 3 turns of the pan. Add pancetta, season with black pepper and brown lightly. Stir in garlic, chili and whites of spring onions. Stir for a few minutes and add the wine.
When pasta is about ready, beat the egg yolks with about 1 cup of warm saffron stock and temper the eggs.
Toss the spring onion-pancetta mixture and tempered egg yolks with the pasta. Toss in a few handfuls of Pecorino and Parmigiano. Garnish with parsley and greens of spring onions.