Karashi Renkon - deep fried lotus root stuffed with Japanese hot mustard miso on a bamboo basket.

Karashi Renkon (Lotus Root with Japanese Mustard)

Course: Appetizer, Side Dish
Cuisine: Japanese
Keyword: lotus root, spicy
Prep Time: 30 minutes
Cook Time: 10 minutes
Total Time: 5 hours 40 minutes
Servings: 6 (appetizer)
Karashi Renkon is a popular regional dish on the island of Kyushu in Japan. A mixture of miso and Japanese karashi hot mustard is stuffed in lotus root, coated in turmeric flour batter, and deep-fried until a crispy crust forms.


Japanese Mustard Miso


  • 1 large egg
  • 1 cup all-purpose flour (120 g)
  • 1 Tbsp turmeric powder
  • ¼ tsp salt (kosher or sea salt; use half if using table salt)
  • ½ cup water (120 ml)


  1. Gather all the ingredients.
    Karashi Renkon Ingredients

Day 1

  1. Peel the lotus root and scrape the sides lengthwise with a fork. Creating a rough surface helps the batter stick to the lotus root.
    Karashi Renkon 1
  2. Trim both ends. If the lotus root is longer than 4 inch in length, cut it in half. Place the lotus root in a saucepan and add just enough water to cover. Add 1 tsp rice vinegar to prevent the lotus root from changing color.
    Karashi Renkon 2
  3. Bring the water to a boil and cook for 6 minutes. Transfer to a sieve and let it stand upright to dry until the holes are completely dry (excess moisture will dilute the fillings).

    Karashi Renkon 3
  4. In a bowl, combine 2 tsp karashi mustard and 1 Tbsp warm water and mix well.

    Karashi Renkon 4
  5. In a medium bowl, combine 5 Tbsp panko, 1 Tbsp mirin, 1 Tbsp sugar, and 5 Tbsp white miso and mix well.
    Karashi Renkon 5
  6. Add in the karashi mustard and mix all together.
    Karashi Renkon 6
  7. Pile the mustard miso mixture into a small mound on a plate. Press the lotus root into the mixture repeatedly until it fills up the holes and overflow from the top.
    Karashi Renkon 7
  8. Wipe off the excess mustard and let it stand upright on a clean plate. Cover with plastic wrap and keep in the refrigerator overnight for the best result (or minimum 5 hours).
    Karashi Renkon 8

Day 2

  1. Next day, remove the excess mustard miso mixture from the top and bottom and wipe off the excess moisture with paper towel.
    Karashi Renkon 9
  2. In a large bowl, beat 1 egg and sift 1 cup flour, 1 tbsp turmeric and ¼ tsp kosher salt into the bowl.
    Karashi Renkon 10
  3. Mix all together and gradually add ½ cup water.
    Karashi Renkon 11
  4. Stir until blended. The batter will be sticky and thick so it coats the lotus root well.
    Karashi Renkon 12
  5. Add 3 cups oil in a small pot and bring the oil to 350 ºF (180 ºC) over medium heat. The oil should cover the lotus root when deep frying. Therefore, a smaller pot works better so you can use less oil.
    Karashi Renkon 13
  6. Insert 2 bamboo skewers into the side of the lotus root. Dredge the lotus root in the batter.
    Karashi Renkon 14
  7. Using a spoon, make sure the lotus root is completely covered with the batter. Ideally, you want to smooth out the surface. (I know, it can be challenging, as the batter tends to fall off when you touch it. Let’s do your best.).
    Karashi Renkon 15
  8. When the oil reaches 350 ºF (180 ºC) (or drop a small amount of the batter in the oil and if it floats back to the surface in a few seconds, it’s ready.), submerge the lotus root, holding the bamboo sticks. Deep fry for 5 minutes.  Make sure the lotus root is NOT TOUCHING the bottom of the pot; otherwise, the batter will stick to the bottom. Deep fry until crisp and golden brown. Drain excess oil on the wire rack until it’s cool enough to handle.

    Karashi Renkon 16
  9. Slice the Karashi Renkon into 8 mm thick rounds. Serve immediately.
    Karashi Renkon 17

Recipe Notes

Recipe by Namiko Chen of Just One Cookbook. All images and content on this site are copyright protected. Please do not use my images without my permission. If you’d like to share this recipe on your site, please re-write the recipe in your own words and link to this post as the original source. Thank you.