Tsukune is a term that means “kneaded and shaped into a round shape”. It usually means a dish made with finely ground and flavored chicken or fish. Chicken tsukune are very well suited to bentos, since they are soft and stay nice and moist. They are also gluten-free (no breadcrumbs!), if you take care to use a gluten-free cornstarch or potato starch and soy sauce.
Today I’ll show you how to make two type of chicken tsukune from the same basic recipe. First, the very traditional stewed tsukune dumplings, cooked in a broth with carrots (tsukune-ni).

And here are some pan-fried tsukune, or tsukune baagaa (tsukune burgers) - actually mini-burgers to fit neatly into a bento box.

Where I live, I can’t normally get ground chicken, which is a standard item in Japanese supermarkets. But that’s ok, since I’d rather grind my own chicken anyway. I use skinned and boneless chicken thighs, which have enough fat to keep the tsukune moist. If you have a food processor, this is a breeze to make; if not, you will have to buy ground chicken or get a butcher to grind it up for you.
This amount will make about 24 small dumplings, 10 mini-burgers, or a combination. (I usually make 6 mini-burgers and make the rest into dumplings.)
Put the chicken thighs in the bowl of a food processor. Pulse several times to ground coarsely. Add the rest of the ingredients, and process until a smooth paste is formed. You may need to scrape down the bowl a couple of times.
For the broth:
Put everything in a small pan and bring to a boil. Using two teaspoons, form the tsukune mixture into small balls (they’ll be sort of rugby ball (American football) shaped, like quenelles) and drop them into the broth. Wetting or oiling the spoons will make the tsukune mixture less sticky. As you can see, the dough is a bright orange-pink color from the carrot and dark meat.

Just let it boil away until the carrots are cooked through, about 15 minutes, stirring carefully a few times. To pack in a bento box, strain off the broth, then drizzle just a bit of it on top.
Stewed tsukune keeps, well covered, in the refrigerator for 2-3 days. They also freeze nicely, with a bit of the broth. Just defrost them in the microwave.

Tsukune burgers are very light and soft, almost fluffy — a nice change from burgers made from beef.
Make small burger shapes using two tablespoons, and panfry them with a little bit of oil in a nonstick frying pan until golden brown on both sides. They are great as-is, but I added a tablespoon or so of oyster sauce to glaze/sauce them. You could also combine equal amounts of mirin, sake and soy sauce with a pinch of sugar for a more traditional teriyaki-type glaze.
Tsukune burgers also freeze well. I freeze them unglazed. To defrost, put into an unoiled nonstick frying pan over low-medium heat, put on a tight fitting lid and steam-cook them until warmed through. This only takes a few minutes. Add the glaze or sauce of your choice at this point.