Peel the cucumber into ribbons with a vegetable peeler. Trim the pak choy and separate the leaves.
Step 2 — Pickle cucumber
Combine 2 tsp white vinegar and 1 tsp sugar in a large bowl. Add the cucumber and toss to combine. Set aside to pickle, tossing occasionally, until needed.
Step 3 — Cook dumplings
Heat a generous drizzle of vegetable oil in a medium deep frypan over medium-high heat. Cook the dumplings, without turning, for 2-3 mins until golden on one side. Carefully add 60ml (¼ cup) water (take extra care when adding it to the hot pan as the oil can spit). Cover and steam for 2 mins.
Step 4 — Add pak choy
Arrange the pak choy on top of the dumplings. Cover and cook for a further 1 min or until the dumplings and pak choy are tender. Remove the pan from the heat.
Step 5 — Serve up
Drain the cucumber, reserving the pickling liquid. Combine the Japanese dressing, reserved pickling liquid, 1 tsp soy sauce and ½ tsp chilli flakes, if using, in a bowl and season with pepper. Divide the dumplings and pak choy among bowls. Drizzle with the sauce. Top with the pickled cucumber and fried shallots and enjoy!
Step 6 — Make it yours
Like it herby? If you have some on hand in the crisper drawer or veggie garden, scatter over a handful of coriander or parsley leaves for a burst of freshness.