3 tablespoons extra-virgin olive oil (EVOO)
1/3 pound meaty guanciale or pancetta, diced
2 leeks, quartered lengthwise, rinsed and dried, thinly sliced
1 bulb green garlic, stalk removed and cloves peeled, or 4 cloves, thinly sliced or chopped
1 teaspoon black pepper
½ cup white wine
½ cup flat-leaf parsley, finely chopped
1 pound bucatini
6 egg yolks
½ cup each freshly grated Parmigiano-Reggiano and Pecorino Romano cheese, plus more to pass at table
1 tablespoon lemon zest and juice of 1 small lemon
Heat a large pot of water to a boil for pasta.
Heat a large skillet over medium heat with EVOO, 3 turns of the pan, add guanciale or pancetta and render 2-3 minutes. Add leeks and garlic and season with pepper, stir 3-5 minutes. Add wine to pan and let it absorb, turn heat down to low, and add parsley.
Season pasta water liberally with salt and cook pasta 1-2 minutes less than package directions.
Whisk up egg yolks, cheeses, and zest and juice of 1 lemon.
Just before draining pasta, add a mug (about 1 1/4 cups) of boiling salted water to egg yolks while whisking. Drain pasta or transfer with spider to leeks in skillet, pour eggs over, turn off heat, and toss pasta with tongs 1-2 minutes to combine; adjust salt and pepper to taste. Serve pasta in shallow bowls with more cheese to pass for topping.