Bring a large pot of water to a boil for the pasta. When boiling rapidly, salt water and cook pasta to al dente. Heads up: reserve 1/2 to 3/4 cup of starchy water just before draining pasta.
Heat a large skillet over medium heat with EVOO, 3 turns of the pan. Add pancetta, season with black pepper and brown lightly. Stir in garlic, chili (if using), whites of scallions, zest the lemon over the pan and stir in thyme. Stir 2-3 minutes then add wine and reduce by half, 1-2 minutes. Reduce heat to low.
When pasta is about ready, beat the egg yolks with the reserved starchy water to temper. Add lemon juice, parsley and greens of onions to pan.