In a large dish, whisk together the cumin, garlic, chilli, hoisin sauce, soy sauce, vinegar, and 1 Tbsp olive oil. Add lamb cutlets and turn to coat. Set aside to marinate for 10 min.
Cut broccoli and cauliflower into florets, slice cabbage into bite-size pieces.
Drizzle 2 Tbsp oil into a wok or large skillet over medium-high heat. Add broccoli, cabbage, and cauliflower, and stir fry for 5 min, until vegetables are tender-crisp and starting to char. Drain marinade off of cutlets into the wok, add ¼ cup water, and cook for a further minute or two, until sauce is heated through and starting to thicken.
Heat a heavy-based pan or bbq to medium. Cook lamb cutlets for 2 - 3 min per side, or until cooked to your liking.
Serve cutlets with steamed rice, stir fried veggies, spring onion, chilli flakes and sesame seeds.
Tips
Shaoxing wine can be found at any Asian grocery store. It can be substituted with dry cooking sherry if necessary.