Add ¼ onion, 250 g ground chicken, 5 perilla leaves (shiso), 1 tbsp Japanese mayonnaise, 1 tsp ginger root, ½ tsp yellow miso paste (awase), 1 tsp Chinese-style chicken bouillon powder, 2 tbsp potato starch (katakuriko) and 1 pinch ground black pepper to a large mixing bowl.
Mix with a silicone spatula until the ingredients are evenly distributed throughout and the mixture has combined and reached a sticky consistency.
Divide into 5 equal pieces (for balls, divide into 12-15 pieces to make 4-5 skewers with 3 meatballs on each). Grease your hands with oil and shape into oblongs or balls. (If you don't want to get your hands dirty, transfer each piece to a piece of baking parchment and shape using a spoon.)
Mix 1 ½ tbsp Japanese soy sauce (koikuchi shoyu), 1 ½ tbsp mirin, 1 tsp red wine and 1 tbsp sugar in small bowl and set it by the stove.
Heat pan on medium and add a drizzle cooking oil. Once hot, carefully place the tsukune in the pan and fry until lightly browned underneath. Flip and repeat on the other side.
Once both sides are browned and the meat is cooked through, turn off the heat and pour the sauce into the pan, it will thicken in the residual heat. Move the tsukune around the pan until evenly coated with sauce all over.
Push onto skewers, sprinkle with sesame seeds and spring onion. Optional: serve with 1 pasteurized egg yolk for dipping. Enjoy!
Notes
Squeeze the grated onion hard: Grated onion hides more water than it looks. I skipped a proper squeeze once and the mixture went too loose to shape. Squeeze firmly, then once more.Oil your palms or use parchment: This mixture grips dry skin like tape. Shape on parchment strips with a spoon and your hands never touch the meat at all.Read the drip for glaze doneness: Lift the spatula. When the glaze falls in a slow, heavy drip instead of running off thin, it is ready to coat.Rest before skewering: Fresh from the pan, tsukune are at their most fragile. Wait a few minutes or steady each one with tongs, then push the skewer through lengthwise.No shiso, use green onion: You trade the cool perfume for a gentle allium sweetness and the skewer stays squarely in yakitori territory.