Vegan udon noodle soup, also known as kitsune udon, is a comforting Japanese noodle soup with thick, chewy udon in a light, umami-rich broth. Traditionally, it is topped with sweet seasoned tofu called inari age, which gives the dish its signature flavour and its name: kitsune, or "fox," because foxes are said to love fried tofu in Japanese folklore.
This vegan version keeps everything you love about the classic. The broth is made with a plant based dashi that is delicate yet full of flavour, the noodles are satisfyingly bouncy, and the tofu topping adds just the right touch of sweetness. It is quick enough for a weeknight, cozy enough for a cold day, and easy to customise with different toppings to make it your own.
Why You'll Love This Vegan Udon Noodle Soup
- A classic Japanese noodle soup made vegan - all the flavour of traditional kitsune udon, with a plant based broth and toppings.
- That sweet tofu topping - inari age (seasoned aburaage) gives the soup its signature kitsune flavour.
- On the table in 30 minutes - quick prep and simmering make it weeknight-friendly.
- Easy to customise - keep it simple or change it up with toppings like tempura, mushrooms, crispy tofu, pickled radish, chili, or greens.
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Ingredients
Serves 2 | Prep time 10 minutes | Cooking time 20 minutes
This section gives you an overview of the ingredients with extra tips and guidance. For exact quantities and the full step by step method, head to the recipe card.
To make vegan udon noodle soup, you will need:
- Aburaage (fried tofu sheets)
- Vegan dashi
- Soy sauce
- Mirin
- Sugar
- Sake
- Salt
- Fresh udon noodles (or frozen if fresh aren't available)
- Pak choi
- Spring onions
- Shichimi togarashi (optional, for spice)
Ingredient notes
- Aburaage is fried tofu that gets simmered in broth to make inari age, the sweet topping that makes this kitsune udon special. If you enjoy this preparation, try our vegan sushi caterpillar roll for another classic use.
- Vegan dashi is the base of the broth. It is usually made from kombu (kelp) and shiitake mushrooms, giving a delicate umami flavour. You can use a vegan-friendly instant version, but if you have time it is worth making your own. Here is our vegan dashi recipe.
- Pak choi (also called bok choy) and spring onions add freshness and crunch. You could also use other leafy greens if you prefer.
- Shichimi togarashi is optional but highly recommended for a subtle chili heat and citrus kick.
Which udon noodles are best for kitsune udon noodle soup?
Fresh udon noodles are the gold standard and give the best chewy texture that makes this dish so satisfying. Frozen udon is a close second and still works well if you can't find fresh. Dried udon noodles are not ideal as they don't absorb the broth as well and they don't have that same bouncy texture. If you're looking for another way to enjoy udon, try our yaki udon recipe, where the noodles are stir-fried with tofu, vegetables and sauce instead of simmered in broth.
How to Make Vegan Udon Noodle Soup
Making vegan udon noodle soup has two simple stages. First, prepare the inari age by simmering fried tofu in a sweet soy broth until it absorbs all that flavour. Then, while the tofu rests, you will make the soup base, cook the noodles, and bring everything together in the bowls with fresh toppings.
Prepare the inari age (seasoned tofu topping)
- Boil half a kettle of water and pour it over the aburaage in a bowl. This quick rinse removes excess oil, which helps the tofu soak up more flavour later. Gently dunk for a minute using chopsticks or the back of a fork or spoon.
- Drain and rinse under cold water, then squeeze out the moisture until the slices feel light and spongy.
- Place vegan dashi, sugar, and soy sauce in a saucepan and bring to a gentle simmer. Stir until the sugar dissolves.
- Add the aburaage and simmer for 10-15 minutes, until most of the liquid is absorbed.
Tip: Use a drop lid or small plate to weigh the tofu sheet down in the broth. This keeps it submerged so it soaks up every bit of seasoning.
- Let the tofu cool slightly, then slice into triangles. At this stage, it becomes inari age, the sweet tofu topping that gives kitsune udon its name.
Make the broth, cook the noodles, and assemble
- Combine vegan dashi, mirin, sugar, soy sauce, sake, and a pinch of salt in a saucepan. Heat gently until it starts to simmer, then keep warm without boiling.
Tip: Take your time with the broth, it's the heart and soul of this dish. Taste as you go, adjusting lightly with soy sauce or sugar if needed. A tiny tweak makes a big difference so add only very small amounts at a time.
- Thinly slice the spring onions into disks, taking your time to get a nice even texture. Set aside.
- Chop the Pak Choi leaves. I like to slice the stalks thinly and keep the leaves a little thicker since the stalks are firm whereas the leaves are more tender.
- Bring a large pot of water to the boil. Add the udon noodles for 1 minute, gently separating any strands with chopsticks or a fork. Fresh or frozen udon will quickly loosen and take on the flavour of the broth once added to the bowls.
- Drain and divide the noodles between two serving bowls. You can multiply quantities (and packets of udon) in this recipe if cooking for a larger group.
- Lay the inari age slices over the noodles, then ladle in the hot broth. The udon will continue to absorb flavour as it sits in the soup.
- Top with pak choi and green onions. You can keep them fresh for a bright crunch, or blanch them briefly if you prefer a softer bite.
Tip: You can also swap in other greens if you like. Spinach, napa cabbage, broccoli, or Japanese greens like mizuna or komatsuna (Japanese mustard spinach) all work beautifully. Choose something that softens slightly in the broth while keeping its colour and texture.
- Finish with a sprinkle of shichimi togarashi if you like a little heat. You can also add thinly sliced fresh red chili for a sharper kick, a spoonful of chili paste or a drizzle of chili oil for even more warmth. Serve immediately while everything is piping hot
Substitutions
- Gluten free udon noodle soup - Swap the udon noodles for rice noodles or soba made with 100% buckwheat, and use tamari instead of soy sauce in the broth. You'll still get a light, umami-rich soup that's fully gluten free.
- Soy free vegan udon - Replace the inari age topping with fried mushrooms or vegetable tempura, and season the broth with coconut aminos, Bragg's liquid aminos, or Noya sauce. This keeps the depth of flavour without the soy.
Variations
- Make it spicy - Stir a spoonful of chili paste or a drizzle of chili oil into the broth for extra warmth. Fresh sliced chili or chili flakes sprinkled on top also work beautifully.
- Mixed mushroom udon - Pan fry mushrooms such as shiitake, oyster, enoki, or chestnut until golden. Finish with toasted sesame seeds and use them as a hearty topping for your vegan udon noodle soup.
- Green vegetable kitsune udon - Add variety with extra greens like spinach, napa cabbage, or mizuna. Pan fry them quickly in mirin, sugar, and soy sauce for a sweet-savoury finish. You can use our soy seared pak choi recipe as a method for any leafy green.
Storage
Vegan udon noodle soup is always best enjoyed fresh while the noodles are still bouncy and the broth light. If you have leftovers, keep the broth and inari age in separate airtight containers in the fridge for up to 3 days. Noodles are best cooked fresh, but you can store them separately for a day if needed. When reheating, warm the broth gently on the stove and avoid boiling so the flavour stays delicate. Combine with freshly cooked or reserved noodles just before serving.
FAQ
Most udon noodles are vegan, as they're typically made from just wheat flour, water, and salt. Always check the packet though, because some brands add egg or other ingredients. Fresh or frozen udon usually works best for vegan udon noodle soup.
Traditional kitsune udon is not vegan because the broth is often made with dashi containing bonito (fish flakes). In this vegan kitsune udon recipe, we use a plant-based dashi and keep the sweet inari age tofu topping, so you get all the flavour without the fish.
Udon noodle soup is a classic Japanese dish made with thick, chewy udon noodles in a light broth. Kitsune udon is the version topped with seasoned fried tofu, giving it a signature sweet and savoury balance. Our vegan udon noodle soup recreates the same comforting flavours with a fully plant-based broth.
"Kitsune" means fox in Japanese, and folklore says that foxes love fried tofu. That's why the dish topped with sweet inari age tofu is called kitsune udon. It's a simple story that connects the food with Japanese tradition.
A traditional udon broth is made from dashi (a stock often containing bonito flakes), seasoned with soy sauce, mirin, and a little sugar. In vegan udon noodle soup, we swap this for kombu (kelp) and shiitake mushroom dashi, which gives the same delicate umami without the fish. You can check out our vegan dashi recipe if you'd like to make the broth from scratch.
Yes, it's easy to make a gluten-free version. Use tamari instead of soy sauce in the broth, and choose gluten-free noodles such as rice noodles or soba made with 100% buckwheat. You'll still have the same warming, umami-rich soup.
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📖 Recipe
Vegan Udon Noodle Soup (Kitsune Udon Recipe)
Ingredients
For the inari age (seasoned tofu topping):
- 2 aburaage (fried tofu sheets)
- ⅓ cup vegan dashi
- 2 ½ teaspoons sugar
- 2 teaspoons soy sauce
For the soup broth:
- 2 ½ cups vegan dashi
- 1 tablespoon mirin
- 1 ¼ teaspoons sugar
- 5 teaspoons light soy sauce
- 1 teaspoon sake
- Small pinch of salt
For the noodles and toppings:
- 2 packets of fresh udon noodles (about 400g total)
- 4 medium leaves of pak choi (or other greens)
- 2-3 spring onions, finely sliced
- Shichimi togarashi (optional, to serve)
To cook the noodles:
- Large pot of water to boil (about 2 litres)
Instructions
Prepare the inari age (tofu topping):
- Pour boiled water over the aburaage in a bowl, dunk for 1 minute to remove excess oil, then drain, rinse, and squeeze dry.
- In a small saucepan, combine ⅓ cup vegan dashi, sugar, and soy sauce. Simmer with the aburaage for 10-15 minutes until most of the liquid is absorbed.
- Let cool, then slice into triangles.
Make the broth, prep toppings, and cook the noodles:
- In a saucepan, combine 2 ½ cups vegan dashi, mirin, sugar, light soy sauce, sake, and a pinch of salt. Simmer gently and keep warm (do not boil).
- Thinly slice the spring onions and chop the pak choi, keeping stalks and leaves separate.
- Bring a large pot of water to the boil, add the udon noodles, and cook for 1 minute, gently separating the strands. Drain well.
Assemble the udon noodle soup:
- Divide the noodles between serving bowls.
- Add inari age slices on top, then pour over the hot broth.
- Garnish with pak choi and spring onions, sprinkle with shichimi togarashi if desired, and serve immediately.
Notes
- For the best flavour, make your own vegan dashi instead of using instant.
- Fresh or frozen udon noodles give the best chewy texture. Avoid dried if possible.
- Don't let the broth boil - it can dull the delicate umami.
- Top with vegan tempura instead of inari age for a crisp variation.
- Serve immediately while hot for the best texture and flavour.
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