125 gmpotato starch (see note)1Lebanese cucumber For deep-frying:vegetable oil150 gmkimchi (see note), coarsely chopped2spring onions, thinly sliced4soft sesame seed hamburger buns (about 12cm in diameter), splitMarinated chicken4chicken thigh fillets (120gm each)1 tbspsalt1 tbspcaster sugar100 mlChinese rice wine2 tbspsesame oilGochujang mayonnaise150 gmJapanese mayonnaise35 gmgochujang (see note)
For marinated chicken, combine chicken thighs with marinade ingredients in a bowl. Mix thoroughly with your hands and refrigerate to marinate (at least 2 hours or overnight). Just before cooking, stir in potato starch to form a batter.
Using a mandolin or very sharp knife, slice cucumber into 3mm-thick rounds, place in a bowl and sprinkle with 1 tsp salt. Mix and set aside for 25 minutes to draw out liquid, then squeeze excess moisture out, rinse under running water, then pat dry with paper towels. Set aside.
For gochujang mayo, mix the mayonnaise and gochujang with a whisk until incorporated. Set aside.
Heat oil to 160C in a deep saucepan or deep-fryer. Carefully add chicken thighs in batches, ensuring they don't stick to the bottom of the pan, and fry until cooked (6-9 minutes; be careful, hot oil may spit). Drain on paper towels and season to taste.
Meanwhile, steam burger buns in a steamer, or toast under a hot grill (1 minute).
To serve, spread a generous dollop of mayonnaise on each of the bun bases, then top with a chicken fillet, spoon a generous amount of kimchi on top along with salted cucumber and spring onion. Spoon a little more mayo on the bun tops to taste, place on top and serve.
Note Potato starch, kimchi and gochujang
(Korean chilli paste) are available from Korean and most Asian food