Wholesome clear Japanese soup with onions and mushrooms.

Japanese Onion Soup with Mushrooms

This Japanese onion soup with mushrooms is a delicious vegetarian & vegan meal starter. Best of all, it is low in calories and wholesome.
Course Soup
Cuisine Japanese
Prep Time 10 minutes
Cook Time 30 minutes
Total Time 40 minutes
Servings 4
Calories 64kcal
Author Victoria


  • 2 teaspoons grapeseed oil or other light vegetable oil
  • 1 large white or yellow onion diced
  • Pinch of sea salt and pepper
  • 1/4 tsp ground ginger
  • 2 garlic cloves minced or pressed
  • 8 cups unsalted chicken or vegetable broth
  • 4 to 6 crimini or baby portabella mushrooms sliced thinly
  • 2 teaspoons light miso
  • 2 teaspoons tamari or soy sauce
  • Sea salt and pepper to taste
  • 2 sliced scallions for topping


  • Heat the oil in a large pot over medium heat. Add the onions and sauté with a pinch of salt and pepper until they begin to soften, about 5 minutes.
  • Add the ginger and garlic. Sauté for another minute until fragrant.
  • Add the broth to the pot and the mushrooms. Bring to a boil then reduce the heat to simmer for 27 minutes.
  • Whisk in the miso until fully dissolves. Add the tamari and simmer for another 3 minutes. Season to taste with more salt and pepper if needed.
  • Serve in bowls with chopped scallions on top.


Suggested Optional Toppings
It is nice to have some bowls of toppings that everyone can choose from to add to the top of the soup. I personally like a little crunch with fried onions. Here are some suggestions for additional toppings:
  •  Crispy fried onions, either store-bought or homemade
  •  Julienned slices of fresh cucumber
  •  Mung bean sprouts 
  • Toasted sea vegetables, such as nori krinkles 
  • Small cubes of firm tofu 
  • Gomashio (toasted sesame seeds seasoning)


Calories: 64kcal | Carbohydrates: 6g | Protein: 3g | Fat: 3g | Sodium: 2001mg | Potassium: 432mg | Sugar: 1g | Vitamin A: 1.2% | Vitamin C: 44.3% | Calcium: 4.2% | Iron: 6.8%