Boil the 220 grams spaghetti in a pot of well-salted water (1 tablespoon per 5 cups of water) for 1-2 minutes less than what the package says.
220 grams spaghetti
About 6 minutes before the pasta is ready, add the 2 teaspoons olive oil, 70 grams onion and 70 grams button mushrooms to a preheated frying pan over medium heat. Sauté until the vegetables just start to brown.
2 teaspoons olive oil, 70 grams button mushrooms, 70 grams onion
Add the 120 grams thick-cut bacon and continue sautéing until bacon just starts to render out some fat.
120 grams thick-cut bacon
Add the 70 grams mild green pepper, and when the pasta has about a minute left to go, add the ⅔ cup ketchup, along with a ladle of boiling liquid from the pasta.
⅔ cup ketchup, 70 grams mild green pepper
Add the 2 teaspoons soy sauce, 1 tablespoons cultured unsalted butter and ½ teaspoon black pepper and stir this together to emulsify the butter.
1 tablespoons cultured unsalted butter, 2 teaspoons soy sauce, ½ teaspoon black pepper
When the spaghetti is done, add it to the sauce and finish cooking it in the sauce. If the noodles start sticking together, add more of the pasta's boiling liquid to loosen the sauce.
When the pasta is cooked to your liking, serve the Spaghetti Napolitan with some grated parmesan cheese.