Seared Tuna with Cold Udon

Yesterday was really hot, almost 36ºC. Actually it has been very hot these few weeks and in Switzerland, it is not common to have air conditioning at home. I don’t have much appetite and also do not want to spend too much time in the kitchen. We have been having dinner much later than usual at around 8:30pm or even later at weekends like people in Spain. Peter suggested to have seared tuna last night and I came out the idea of serving it with cold udon. Am glad he liked it a lot, it’s the first time I made the Mentsuyu, Japanese noodle dipping sauce from scratch.


  • 400g sushi quality tuna steak (3.5cm thick)
  • 100g dried Sanuki udon (讃岐), which is thinner than normal udon
  • Mentsuyu (dipping sauce for cold udon, see below)
  • Dipping sauce for seared tuna (see below)

Mentsuyu (Dipping sauce for cold udon):

  • 1.5 cups dashi stock (see below)
  • 3 tbsp Japanese soy sauce
  • 1 tbsp sugar
  •  2 tbsp sake (or 2 tbsp mirin, replacing sake and sugar)
  • 2 tbsp thinly sliced spring onion (served on side)
  • 1 sheet nori seaweed, cut into thin strips (served on side)
  • 1 tsp grated ginger (served on side, optional)


Dipping sauce for Seared Tuna:

  • 3 tbsp soy sauce
  • 2 tbsp sake
  • 1 tbsp fine brown sugar
  • 2 tbsp lemon juice
  • 1 tsp rice vinegar
  • 1 tbsp spring onion (use the greenish white part)
  • 1 tsp grated ginger
  • 1 tsp sesame oil
  • grinded black n’white sesame seeds



  1. Heat up the dashi stock in a saucepan, add in the sake and sugar, bring to boil. Turn off the heat, transfer the sauce to a bowl, cool down or chill in the fridge and half an hour in the freezer.
  2. Boil the udon as instructed from the pack, drain and rinse with cold water to avoid sticking, set aside.
  3. Prepare the seared tuna dipping sauce by mixing all ingredients in a bowl, set aside.
  4. Heat up the friddle grill pan at high heat, sprinkle some salt and black pepper on the tuna steak, oil the pan with some olive oil, then grill the tuna, one side for 1 min, then turn over to the other side for 40 secs, and then lastly the 4 sides briefly for 10 secs each. Using a sharp knife or better a sushi knife, thinly sliced the seared tuna.
  5. Divide the cold udon onto 2 dishes and line the sliced seared tuna on the plate sides, drizzle some seared tuna dipping sauce, the remaining of the dipping sauce will be served on side. Garnish with some nori seaweed. 
  6. Serve the Mentsuyu in individual bowl.  To eat, you dip some udon into the dipping sauce bowl and eat from there. 



If you happen to visit a Japanese groceries, do try out other brands of dried udon. They can be very good with chewy texture.


How to make dashi stock:


  • 1 piece kombu seaweed
  • 30 g bonito flakes
  • 1000ml of boiling water
  1. Whip the kombu seaweed with a damp cloth and then place in a saucepan with 1 litre of boiling water. Leave it for 10 mins. Bring to boil and then discard the kombu seaweed.
  2.  Add in the bonito flakes and bring the liquid to boil for 5 mins. Strain the bonito flakes and you get the dashi stock.
  3. Use the dashi stock as required, the remaining can be kept in freezer for later use.

8 thoughts on “Seared Tuna with Cold Udon

  1. A perfect dish to eat when the temperatures are high. So fresh, light and delicious looking. Yummy!



  2. At this point of time, it’s okay as long as you get it from reliable fish monger. I have asked the Japanese Chef here for sure. But for the first trimester, you do need to be careful.

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