Fill a medium saucepan three-quarters full with water and bring to the boil for the rice. Thinly slice the spring onion. Halve the carrot lengthwise and thinly slice. Coarsely chop the cabbage and Chinese broccoli.
Step 2 — Cook rice
Cook the rice in the pan of boiling water for 12 mins or until tender. Drain.
Step 3 — Brown dumplings
While the rice is cooking, heat 1 tbs oil in a large deep frypan over medium-high heat. Cook the dumplings, without turning, for 2-3 mins until golden on one side.
Step 4 — Steam dumplings
Carefully add 60ml (¼ cup) water (take extra care adding water to the hot pan as the oil can spit and the steam created is very hot). Cover and steam for 3 mins or until the dumplings are tender. Remove from the pan and cover to keep warm.
Step 5 — Stir-fry vegetables
Heat 2 tsp oil in the pan over high heat. Stir-fry the carrot, cabbage and Chinese broccoli for 3 mins. Add 1 tbs soy sauce and 2 tsp white vinegar and season with pepper. Cook, stirring occasionally, for a further 1-2 mins until the vegetables are tender.
Step 6 — Get ready to serve
Combine the tonkatsu sauce, aioli and 2 tsp water in a bowl. Divide the rice, vegetables and dumplings among bowls. Drizzle over the tonkatsu aioli and scatter with the spring onion to serve.