Add salt to plenty of boiling water (10 g of salt to every liter of water is the standard), put in the spaghetti, and cook it.
Slice the onion thinly. Divide the bok choy into the stem parts and the leaf parts and cut into 2 cm wide pieces. Cut the char siu pork into 1 cm wide strips.
Heat up 1 tablespoon of sesame oil in a frying pan and stir-fry the onion. When the onion has wilted, add the stem part of the bok choy and keep stir frying.
Add the char siu to the frying pan and stir-fry some more. Add the tomato ketchup and soy sauce and mix together.
Mix the cooked spaghetti and the leaf parts of the bok choy into the frying pan and stir-fry. Season with salt and pepper.
Drizzle the spaghetti with 1 teaspoon of sesame oil. Transfer the spaghetti to serving plates and sprinkle with white toasted sesame seeds to finish.
Story Behind this Recipe
My family loved spaghetti Napolitan (a Japanese-style pasta dish). I wanted to give them a variation of it sometimes, and this recipe is the result. I used Chinese ingredients like bok choy and char siu instead of the usual western ingredients (like bell peppers, mushrooms, wiener sausages etc.) and just added 100% sesame oil! This transforms the usual spaghetti Napolitan into a fragrant, rich Chinese-style dish.
Cook the spaghetti in lots of boiling water. Please boil the spaghetti according to the instructions on the packet. Stir fry the stem part of the bok choy leaves first, and then add the leaf part. Adjust the amount of salt and pepper and toasted sesame seeds to taste.