In a bowl, mix the mayo, miso, mustard, honey, lemon juice, and 1 tsp salt. Scoop out 60 ml of the mixture for the marinade and refrigerate the rest for the dressing.
Coat the chicken with the marinade and refrigerate, covered, for at least 30 minutes (or overnight for extra flavour).
Preheat the oven to 190°C. Line a baking tray with foil and place a wire rack on top. Arrange the chicken on the rack and roast for 30–45 minutes, or until the thickest part reaches 74°C.
Toss the sliced cabbage with some of the reserved dressing. Sprinkle over sesame seeds or furikake.
Let the chicken rest for 5 minutes after roasting, then drizzle with the remaining dressing. Serve with the slaw.