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Japanese Ketchup Spaghetti (Spaghetti Napolitan) on a white oval plate on a red woven placemat with pepper grinder and Tabasco chili sauce in the background

Napolitan Pasta (Japanese Spaghetti with Ketchup)

Prep Time10 minutes
Cook Time20 minutes
Total Time30 minutes
Author Yuto Omura
Servings 2 portions

Ingredients 
 

For the Pasta

  • 2000 ml water
  • 1 tbsp salt for the pasta water
  • 200 g dry spaghetti 1.7-1.8 mm thick

Fillings

  • 3 hot dog sausages sliced diagonally 1.5 cm thick, or bacon
  • 100 g onion sliced 3-5 mm thick along the grain
  • 75 g green bell pepper cut into 5 mm strips along the grain
  • 50 g button mushroom sliced 3-4 mm

Sauce

  • 1 tbsp olive oil
  • 4 tbsp tomato ketchup for cooking down
  • ½ tsp sugar
  • ½ tbsp Worcestershire sauce Japanese-style, or Lea & Perrins
  • ½ tsp Japanese soy sauce koikuchi shoyu
  • 2 pinches salt for seasoning the fillings

To Finish

  • 3 tbsp reserved pasta water
  • 1 tbsp milk or reserved pasta water
  • 1 tbsp butter
  • 2 tbsp tomato ketchup for finishing
  • 2 tbsp grated parmesan cheese
  • ¼ tsp ground black pepper freshly ground, coarse
  • dried parsley as needed
  • Tabasco sauce optional, to taste

Instructions 

  • Pour 2000 ml water into a large pot and bring to a rolling boil. Add 1 tbsp salt and 200 g dry spaghetti. Loosen the strands with chopsticks for the first 30 seconds, then boil for the package time plus 1-2 minutes.
    dried spaghetti boiling in a pot of water on the stove
  • While the spaghetti boils, heat 1 tbsp olive oil in a frying pan over medium heat. Lay in 3 hot dog sausages (sliced) and cook for 2-3 minutes, until the cut sides are browned and fat seeps out.
    hot dog sausages frying in a wok on the stove top
  • Add 100 g onion and a pinch of salt. Stir-fry for a few minutes, until soft and translucent.
    sliced onion and hot dog sausages frying in a wok on the stove top with wooden spatula
  • Add 50 g button mushroom and the second pinch of salt, and stir-fry for 1-2 minutes, until the water they release is gone. Add 75 g green bell pepper and stir-fry for 30-60 seconds.
    frying hot dog sausages, onion, button mushrooms and green bell pepper in a wok on the stove top.
  • In a small bowl, mix 4 tbsp tomato ketchup, ½ tsp sugar, ½ tbsp Worcestershire sauce and ½ tsp Japanese soy sauce.
    Push the fillings to the edge of the pan and pour the mixture into the open space. Over medium heat, spread it out and pull it back together with a spatula for 60-90 seconds without stopping.
    Sautéed spaghetti Napolitan ingredients pushed to the side of the wok with sauce in the empty space
  • Toss everything together until evenly coated and turn off the heat.
    Ingredients and sauce for spaghetti napolitan mixed together in a wok on the stove top.
  • When the spaghetti has 1 minute left, return the pan to low heat. Reserve about 100 ml pasta water in a cup, then tip the spaghetti into a colander and drain it lightly, with no hard shaking.
    Increase the frying pan's heat to medium and add 3 tbsp reserved pasta water, 1 tbsp milk (or an extra tbsp pasta water) and the spaghetti. Toss fast over the heat until the sauce clings to the noodles and shines instead of pooling.
    Spaghetti Napolitan in a wok on the stove top.
  • Turn off the heat. Stir in 1 tbsp butter, 2 tbsp grated parmesan cheese and ¼ tsp ground black pepper, one after another in that order. Taste, and add salt if it needs more.
    Spaghetti napolitan topped with butter, parmesan cheese and ground black pepper in a wok on the stove top.
  • Add 2 tbsp tomato ketchup off the heat and mix until evenly distributed.
    Spaghetti napolitan with extra ketchup in a wok on the stove top
  • Twist the spaghetti with tongs and pile it high on each plate. Sprinkle with extra grated parmesan cheese, dried parsley and Tabasco sauce on the table. Enjoy!
    Lifting Spaghetti Napolitan on a fork

Notes

Boil the spaghetti past the package time: Napolitan is not an al dente dish. The time on the package assumes a firm center. What this dish wants is a soft noodle that has taken up water all the way through.
Cook the ketchup down over medium, no higher: A home burner heats a frying pan unevenly. Over high heat the ketchup scorches easily and turns bitter, and with sugar stirred in, it scorches faster still. Medium or medium-low are the safe bets here.
Keep the second ketchup off the heat: Raw ketchup that never meets the flame brings tang and aroma back over the cooked-down sauce.
Hold the heat once the noodles go in: Pasta water and sauce bind best while the pan is hot and the toss is fast. If you mix slowly over low heat, the oil is likely to stay split off.
Fix a flat taste with extra salt & pepper: Avoid adding extra ketchup, which brings extra water and thins the sauce.