Deep-Fried Tuna with Red Onion (Maguro no tatsuta age 竜田揚げ)

friedtunapHigh quality, raw tuna is one of the most delicious fish treats I can imagine. Unfortunately, I don’t have access to excellent quality product and usually pan-grill tuna steaks, keeping them rare inside. When I saw at Shizuoka Gourmet deep-fried tuna chunks on a bed of red onions I knew I had to prepare them as soon as possible. Despite my seasoning modification, I loved the resulting combination of different flavours and thought this snack was perfect to enjoy with a drink or a starter.

The delicious tuna snack, called “pon kara maguro”, is served in Sushi Ko, an excellent restaurant in Shizuoka I learnt about in a review by Robert-Gilles (from the above-mentioned Shizuoka Gourmet) who was lucky to enjoy the dinner in this extraordinary place. Apart from a crisp bed of sliced red onion, the original version features also momiji oroshi (grated daikon with chilli) and chopped green onion (or rather “negi”). I didn’t have momiji oroshi, so I decided to replace it with raimu koshou, a homemade replacement for yuzu koshou, the famous Japanese yuzu zest and chilli paste. As for shiso leaves, their pungency usually pairs well with fried dishes and it did this time too. In spite of these modifications, the final result was fantastic and definitely worth repeating. (I think it’s also an excellent idea to use frozen and then thawed tuna.) Thank you so much, Robert-Gilles, for this excellent idea.

Visit Shizuoka Gourmet to check the restaurant’s address, to read the whole review and other fascinating food, sake and Japan – related posts that will make you travel far far away to Shizuoka prefecture. 

Actually, thanks to Robert-Gilles I was reminded of deep-fried tuna coated in sesame seeds (Maguro no Goma Age, or Sesame Coated Tuna Nuggets) I posted a long time ago and have completely forgotten:

Sesame Coated Tuna Nuggets (Maguro no Goma Age)
Sesame Coated Tuna Nuggets (Maguro no Goma Age)

Here is the very easy Lemon Zest and Chilli Paste recipe, a twist on the Japanese Yuzu Koshou:

Raimu Koshou
Raimu Koshou

WARNING: If by deep-frying you expect to obtain juicy and super soft tuna, beware: the resulting texture should rather be compared chicken than soft fish.

TIPS: Deep-frying scares many people, but becomes easy and quick with time. Everyone has different preferences of course, but the basic rule to observe is to make sure the food is completely dry before it’s fried (or breaded) to minimise the risk of oil splashes. Personally I prefer deep-frying in a small cooking pan (I have one which is only for deep-frying) using a small amount of oil. I also place the pan as far as possible from myself, just in case the oil splashes. If you are really not comfortable with deep-frying or don’t have enough oil, you can of course shallow fry this dish.

Deep-fried food should “swim” easily, so do not overcrowd the pan (otherwise the temperature becomes lower, the food fries slowly and absorbs more oil).

You will probable have to fry in several batches (unless you have a big deep-frying dish or make a small batch). In order to make sure all the tuna pieces are hot when served, I place a baking dish in the oven at 100°C/212°F, line it with paper napkins and put there deep-fried bits, one by one, until the whole frying process is finished.

Frying oil can be used as long as it doesn’t darken and is always filtered after each use (I usually throw it away after three times, but it depends on what you fry… Fish for example can make the oil smell strong, so keep it only for fish or seafood frying).

Preparation: about 20 minutes

Ingredients (serves two as a small snack or starter):

200 g/about 7 oz fresh tuna cut into bite sized pieces



2 small or medium red onions

yuzukoshou (if you cannot get it or make it, try my replacement version made with lime zest instead of yuzu zest)

chopped shiso or chopped green onions

deep-frying oil (i.e. oil that supports well high temperatures, for example grape seed oil or peanut oil)

Heat the oil in a small pan.

In the meantime peel and slice the red onions.

Place them on two small plates.

Chop the shiso (or green onion).

Season the tuna chunks with salt and coat in cornstarch, shaking off excess starch.

Check if the oil is hot enough (it’s hot enough when a tiny piece of bread thrown into the fat doesn’t “sink” and stays on the surface, instantly browning).

Deep fry the tuna chunks for about 30 seconds in small batches  (the time depends on the temperature of your oil and the size of your pieces).

Place the tuna chunks on paper towels to remove excess oil.

Serve on the sliced onion, topped with shiso and yuzu koshou (or raimu koshou).

You can also serve some soy sauce as a dip.

32 Replies to “Deep-Fried Tuna with Red Onion (Maguro no tatsuta age 竜田揚げ)”

    1. I think it would be difficult to transport a Shizuoka restaurant to Canada 😉 The dish is very easy to prepare though.

  1. I’ve tried deep fried battered tuna – delicious but can easily get a bit dry. The ones I tried were made from the cheapest cut of tuna though.
    I’ve read somewhere that each time oil is heated to high temperatures it changes the properties, so ideally oil should be replaced after 2-3 uses. But we don’t live in the ideal world so I guess we can continue using until it smells terrible. The difference is significant – I know from my fish and chips consuming days:) Every once in a very long while the shop changed its oil and the result was so different.

    1. As I have mentioned, I usually use my oil three times (since oil is really not a luxury, most of us can allow ourselves this “ideal” situation 😉 ). Fast food shops use the oil for many many more frying sessions.

      1. Hi Sissi, I am in Marshall Islands at the moment. Couple of days ago I bought local fresh tuna loin. Quite cheap, little over US$5 a pound. I pan fried it and then remembered your deep fried recipe. If I get the opportunity I will definitely try. I wish I could bring back a few kilo’s…

        1. Lucky you! I hope you will bring lots of culinary inspiration from this distant place.

  2. Somehow the first two links don’t work for me, so I can’t confirm how the original dish is actually called, but I think yours is called maguro no (= tuna’s) tatsuta age (竜田揚げ). By looking at the photo, I can imagine how tasty your tatsuta age can be!

    1. Thank you so much, Hiroyuki. I have just corrected the links (somehow WordPress has put my website address before Shizuoka Gourmet address… thank you for letting me know; now the links work, at least on my computer).
      Thank you for the name! I will proudly add it to the title 🙂

    2. I have just been thinking… isn’t tatsuta age marinated and kara age not marinated? I never really knew the difference.

        1. Haha! I was just in front of my computer when your comment appeared. Due to the time difference it’s rare to be able to exchange messages between Europe and Japan. Thank you so much for the link and explanation.

  3. Hi Sissi,
    I am glad to be here again :)! I have actually commented on your Strawberry Tartlets post, but apparently it didn’t go through. Just want to say hi actually, I miss those days when I was still an active food blogger. Will be blog hopping here again for sure – miss you and even though I don’t like tuna, this dish looks great :)!

    1. Hi CG, thank you for the compliment (I can understand because I really dislike salmon, which everyone else seems to love 😉 ). Actually, I have found this comment in the spam folder… I suspect that your Strawberry Tartlet comment was in spam too… I’m really sorry. I have lots of spam, so I usually look at the first 20 messages and delete the rest… this time I was lucky to notice yours! Thank you for coming back! (I hope now your messages will not end up as spam).

  4. Tuna is rather expensive here and we usually grill it leaving the inside rare; I’m also not a huge fan of deep frying, mainly for health reasons but I actually don’t like it that much either! I do love the tasting notes you’ve provided Sissi, I can see how that relish would go do well with this dish.

    1. Hi, Eva. I think you are the first person I know who doesn’t like deep-fried food in general. Lucky you! Tempura, tonkatsu, Korean sweet & hot chicken, korokke… I would have each of these once a week if I only could 😉 (Tempura and tonkatsu even every day!). As I have said, I usually pan-grill tuna, but this was a nice change (especially for the tuna piece which was not that good quality).

  5. Hi,Sissi. These dishes are very creative onesand look very delicious. I used to eat chicken tatutaage dishes. Thanks for sharing. Wishing you a wonderful weekend.

    1. Thank you, Karen. It’s not as soft as the raw one or the rare one, but I liked its resemblance to dee-fried chicken.

  6. I do agree with you on high quality tuna being the ultimate food! Sometimes I can find a somewhat good quality fresh tuna at Costco (warehouse store), but other than that – forget. We don’t get a lot of good fish here in the desert. 🙂 However, when I do get it, I agree with you – seared and raw in the middle. I love this recipe! What a great treat! Thanks for introducing it to us.

    1. Thank you, MJ. Some people here laugh that the Japanese get the best quality tuna and the rest of the world gets the leftovers 😉 I think that people here even don’t know how to cut tuna and make the best of its different textures… not to mention the freshness. I don’t trust the fishmonger because he has no idea about sushi or sashimi making, so I heat-treat every tuna steak I buy.

  7. Sissi, you wouldn’t believe, I was just looking at a mouth-watering recipe for tuna tataki nigiri (with a creamy ginger sauce 😉 ) and thinking, why don’t I prepare tuna more often? Your deep-fried version brings a whole other element to the mix and I must say, I’m loving the pretty mauve presentation here contrasted against the green raimu koshou. I do enjoy tempura, must admit, although I sometimes wonder if it has more to do with the delicious sauces and crispy batter than the actual contents underneath! (it seems to mask the actual flavour of the food 😉 ). I am not as familiar with tonkatsu… love learning about all this stuff :). (p.s. I have never had deep-fried chicken!! I would not make a very good southerner 😉 ).

    1. Thanks a lot, Kelly. Tempura is addictive… isn’t it? Tonkatsu is pork cutlet coated with panko (similar to bread crumbs) and also deep-fried… It beats by far every Wiener schnitzel or its Milanese cousin… (simply because of deep-frying and the magical panko!). I have posted both tonkatsu and chicken katsu. Both are amazing. Also in sandwiches (if there are any leftovers… I have them very rarely though 😉 ).

  8. I love your deep fried tips! I used to shallow fry more often but lately with growing family AND portion for bento, I realized that I have to cook more amount and shallow fry started not to work (unless I spend more time to deep fry). I totally agree – it’s the easiest way to start practicing deep/shallow frying! This looks delicious! Very refreshing with lime kosho!

    1. Thank you so much, Nami. Raimu koshou makes it very refreshing indeed (by the way, I have to make some more! I have been using it more and more often recently).

  9. I love tuna fish but we don’t have the chance to enjoy it fresh so much here. Because Greece has numerous local types of fish the fish shops sell them more. Nevertheless, I love this dish especially because it has lime zest. I prefer lime from lemon!

    1. Thank you, Katerina. I wish we had the big choice of Greek fish you must have all year round… I wouldn’t miss tuna at all 😉

  10. Oh, I wish I’d seen this post yesterday – it was my father-in-laws birthday and I served tuna, except I didn’t do anything too adventurous with the tuna itself – a simple pan-fry with a rub of oil and some spices before, but I would have loved to do this. It looks amazing, and I bet everyone would have loved it.

    Isn’t tuna a wonderful fish? Incredibly dense, it feels a bit like you’re eating chicken sometimes. It was too filling though – I could easily have split the 4 fillets I had between 8 people, instead of 4 I think.

    1. Thanks a lot, Charles. I love tuna too. When it’s raw it reminds me of raw lean beef (when I was a child steak tartare was made in my family only with loin, so it was quite deep red and lean… like tuna a bit) and when it’s deep-fried it’s like chicken!
      You are right: I find it very filling too (it has a lot of calories actually).

  11. Dear Sissi!
    Sorry for this long delay!
    Just come back from a trip!
    This is just perfect!
    I really the different seasoning and the colors are rally appetizing!
    Well done, hats off!
    Best regards,

    1. Thank you so much, Robert-Gilles. From what I have seen on your blog, the trip was successful. Thank you once more for the recipe and inspiration!

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