Just made a batch tonight. My husband is partial to chicken tsukune. Unfortunately, despite minced chicken being a mainstay in Japanese stores, it is virtually impossible to find it in London. Turkey mince is common enough (too lean!), chicken mince is nowhere. So I make my own - if it’s chicken breast filets I cut them into a rough mince myself with a cleaver, if it’s thigh meat I slice into small pieces and put them in a blender/liquidiser (has more tendons and ligaments)
Once minced, I massage the meat for a couple of minutes with a teaspoon or so of salt. After a while, if you look very closely, you’ll see flecks of white, that’s when the massaging is complete. Add pepper or any other preferred seasoning (I like miso and soy sauce), then massage in a beaten egg BUT don’t massage in more than a dribble at a time so that the egg is incorporated evenly (if you add it all at once the mince “separates”). If you’re using about 300g chicken then add 50-100g of tofu (I’ll press tofu through a sieve), massage in the tofu. Finally I add half a diced onion and that’s my carb concession. If you wish you can stir in some breadcrumbs or a spoon or so of potato starch, but it isn’t necessary.
Take a handful of the mince mixture and squeeze out a dollop of it through the hole made by your thumb and first finger. Size of the dollops are pretty uniform this way.
In a pan, add a thin layer of oil and on a medium heat, once the pan is hot, add the dollops appropriate to the size of the pan (without overcrowding) and then put a lid on the top so that the dollops both fry and cook in their own steam. Leave for about three minutes. Within each dollop, the cubed onion pieces will also release steam and help cook them from the inside. Take the lid off quickly (give it a quick wipe with a towel to get rid of excess water so that it doesn’t fall back and explode into the pan), turn the dollops over - they should be a deep golden brown) and replace the lid and cook for a further 3 minutes or so. If the lid picks up too much water before the end, just remove it quickly, wipe dry and replace over the pan. I generally fry/steam my dollops in two batches.
PS - If exploding water drops are likely to freak you out (a sensible reaction!), you can wrap/tie a damp but not wet towel to the underside of the pan lid. Just make sure the wrapped cloth doesn’t stick out enough so that it can catch fire from the burner.