ketchup pasta on a white speckled plate landscape shot

Napolitan is a popular western-influenced pasta dish made with spaghetti, onion, garlic, mushrooms, bell pepper and (vegan) sausage. This Japanese ketchup spaghetti recipe is quick, easy and perfect for lunch or weeknight dinners!

side angle shot of ketchup spaghetti with veggies and vegan sausage

It’s no secret that Japanese people love ketchup– it’s found used in many dishes like hayashi rice, omurice, ketchup fried rice, Japanese curry and todays recipe that I’m sharing: ketchup spaghetti— known as Napolitan in Japan.

I know, ketchup in spaghetti might sound strange… even make some people cringe but don’t yuck our yum just yet! Try it first, you might like it too– I mean it’s one of the most popular pasta dish across Japan for a reason 😉. You can easily spot this dish at restaurants, cafes, convenience stores, departments stores and served for lunch at schools and offices.

Origin of Napolitan

The exact origin of this western-influenced dish is unknown but here is the most widely known story as to how it came about and became so popular.

Around 1945 (post-World War II), because of the lack of food, the US soldiers that were staying at the New Grand Hotel were eating pasta mixed with ketchup. The head chef Shigetada Irie saw that and wanted to make something more nutritious for them so pulled something together with what they had in the kitchen which were onions, garlic, peppers, ham, pasta and tomato paste. It was loved by the soldiers so much that it became something you could only have at the hotel because at the time, tomato paste was a specialty item that wasn’t easily accessible.

Around 1960, when Japan started to import ketchup from the US, Japanese people began to recreate the dish with ketchup since it was more readily available than tomato paste. It became increasingly popular because of how easy it is to make with the simplest of ingredients. To this day, Napolitan is loved by adults and children alike.

Another interesting theory I read about was that this dish was influenced by yaki udon and yaki soba, which are noodle dishes that are fried in a pan with soy sauce and Japanese flavours. The difference is in the type of noodles and of course, using ketchup.

Now that you know a little more about this dish, let’s get into how it’s made!

ingredients for japanese napolitan ketchup spaghetti in bowls on a beige backdrop

Ingredients needed

There are standard ingredients that you will find in all Napolitan recipes but the sauce is what can make it taste slightly different. One of the best things about this dish, though is it requires minimal ingredients that are pretty much pantry staples. Plus, it’s customizable and there are no rules as to what you can and can’t add. Below is what you’ll need for the most basic recipe:

For the sauce, you’ll need:

  • Ketchup
  • Non-dairy milk
  • Japanese Worcestershire Sauce
  • Soy Sauce or tamari for gluten free

And for the pasta portion, you’ll need:

  • Spaghetti (gluten free if needed)
  • Onions
  • Green Pepper: green is the most common but use whatever pepper you like!
  • Mushrooms: use a variety of different mushrooms for more texture and flavour
  • Garlic
  • Vegan sausages or vegan ham (optional)

Although not common, my mom used to also add spinach for more vegetables. Just remember not to add too much more or you’ll end up needed to make more sauce.

Clearly, I was too hungry and totally forgot the tabasco sauce but definitely add a couple drops if you like a little spice! As well as some vegan parmesan and fresh parsley to garnish.

top photo with bell pepper, onions, mushrooms and garlic cooking and bottom photo with ketchup in it

How to make Napolitan + tips

And not only are the ingredients simple, but it’s also super quick and easy ton make too:

  1. Cook the pasta (just SLIGHTLY before al-dente).
  2. Sauté the garlic, onions, mushrooms, bell peppers and vegan sausage. Tip: scoot the veggies to one side of the pan and cook the sausage until slightly browned on each side and then mix it in with the veggies.
  3. Add all the sauce ingredients and continue to sauté until everything is well coated.
  4. Once the pasta is cooked, add it to the pan and toss with the rest of the ingredients until well coated with the sauce. Season with salt and pepper. Tip: if not using any oil, the noodles may be slightly dry and in that case, just add some cooking water 1 tablespoon at a time to loosen it up.
ketchup pasta with sausage, bell pepper and mushrooms in a pink fry pan

If you’re still skeptical about using ketchup in pasta, I still highly recommend you give it a chance. This might just become your new go-to lazy meal for when you need something ASAP. 😉

napolitan on a white speckled plate with parmesan and parsley

More vegan pasta recipes

If you love spaghetti and pasta, here are some more to try!

If you recreate this vegan Napolitan recipe let me know how you liked it by leaving a comment and rating below or by tagging me on Instagram @Okonomikitchen, I love seeing all of your tasty recreations!
Hungry for more? Be sure to subscribe to my newsletter and follow along on Instagram, Youtube and Pinterest for more deliciousness!

clock clock iconcutlery cutlery iconflag flag iconfolder folder iconinstagram instagram iconpinterest pinterest iconfacebook facebook iconprint print iconsquares squares iconheart heart iconheart solid heart solid icon
napolitan on a white speckled plate with parmesan and parsley

Napolitan (Ketchup Spaghetti) ナポリタン

5 Stars 4 Stars 3 Stars 2 Stars 1 Star

5 from 3 reviews

  • Author: Lisa Kitahara
  • Total Time: 20 minutes
  • Yield: 2 servings 1x


Quick & easy vegan Napolitan made with spaghetti, onion, garlic, mushrooms, bell pepper and KETCHUP.  Have a taste of one of Japan’s most popular pasta dish. 





  • 2 servings spaghetti noodles (200g // gluten free if needed)
  • 2 garlic cloves, minced
  • 1 onion, thinly sliced (220g)
  • 68 button mushrooms, thinly sliced (100g)
  • 1 green bell pepper, thinly sliced (150g)
  • 2 vegan sausages, sliced (200g)

To serve


  1. Cook the pasta following manufacture’s directions on the back.
  2. In the meantime, fry the garlic and onions with some oil (or water for oil-free) in a large pan over medium high heat just until the onions get slightly translucent. Then add in the mushrooms and bell pepper and sauté for 2 minutes. Reduce heat to medium, scoot the vegetables to one side of the pan and cook the sausage on each side for about 1 minute or until you get a bit of browning on it. Then continue to sauté with the rest of the vegetables.
  3. Add all the sauce ingredients and mix it with the rest of the ingredients. Then add the pasta and toss with everything using tongs (this helps the pasta not clump up and break). Season with salt and pepper, to taste.
  4. If the pasta looks dry, add in 1 tbsp of pasta cooking water to loosen the noodles.
  5. Serve immediately with tabasco sauce, vegan parmesan cheese and parsley. Enjoy!


  • Helpful Equipment: large pan, tongs
  • Nutritional Information Disclaimer: Nutrition information is a rough estimate calculated on an online tool (Cronometer).
  • Prep Time: 8 minutes
  • Cook Time: 12 minutes
  • Category: entree
  • Method: stove top
  • Cuisine: vegan, gluten free, japanese


  • Serving Size: 1 serving
  • Calories: 623
  • Sugar: 15.9g
  • Sodium: 1897mg
  • Fat: 8.3g
  • Saturated Fat: 1g
  • Unsaturated Fat: 1.7g
  • Trans Fat: 0
  • Carbohydrates: 103.6g
  • Fiber: 14.6g
  • Protein: 35.9g
  • Cholesterol: 0


ketchup spaghetti on a white speckled plate with napolitan title on top

Okonomi Kitchen is a participant in the Amazon Services LLC Associates Program. When you purchase something through my amazon affiliate links, I earn a small commission that helps me produce consistent content at no cost to you. Thank you for supporting my plant based kitchen! 


About Lisa

I'm Lisa, a home cook, recipe developer and founder of Okonomi Kitchen. Here, you'll find a mix of classic and modernized Japanese recipes, and creative, plant-forward meal inspiration using seasonal ingredients. I hope to share more about Japanese cuisine and culture through food and recipes.

Related Recipes


Leave a reply

Your email address will not be published. Required fields are marked *

Recipe rating 5 Stars 4 Stars 3 Stars 2 Stars 1 Star


  1. Haha! I didn’t know that this was a real thing! I grew up in Hawaii & my mom always had to make two seperate recipes when we had spaghetti. One for us kids, the traditional Italian kind, and one for my dad which was hamburger, ketchup & pasta 😊 I actually like the ketchup one 🤙🏽

  2. Finding dairy-free and egg-free options for my son (and me while I’m nursing) has been a challenge, but Lisa doesn’t disappoint! I wasn’t sure about this one, but it seemed like something the kids would like. And to my surprise it was a big hit with the whole family 🙂 Yum! Will most definitely be adding this to our weekday meals list.

  3. Tweaked it a little because I didn’t have all the ingredients at home. Made it with shell pasta and used onion, peppers, eggplant and baby spinach for the vegetables. Drizzled lots of olive oil. Super tasty and easy recipe!