Roughly chop the choy sum leaves and keep them separate from the stems.
Crush the garlic.
Make the sauce
Put the garlic, ginger, chilli, rice wine vinegar, tamari or soy sauce, honey substitute and 1 tbsp water in a small bowl or jar.
Whisk or shake until combined.
Cook the steak
Season the steak with salt and pepper.
Brush the steak with ghee. Keep any left over for the pan.
Heat the BBQ until very hot.
Cook the steak for 2 to 3 minutes, until well seared on both sides.
Move the steak to a plate, cover it and rest it.
Cook the onion and greens
Heat any leftover ghee in a large frying pan over medium heat.
Add the onion and fry for 5 to 7 minutes, stirring now and then, until tender and caramelised.
Add the broccolini stems, choy sum stems and beans.
Cook for 2 minutes.
Add the broccolini florets.
Cook for 2 minutes.
Add the choy sum leaves and the sauce.
Stir-fry over medium heat for 1 to 2 minutes, until the sauce has reduced slightly.
Finish and serve
Slice the steak into thick strips.
Divide the steak and greens between two bowls.
Scatter with the toasted sesame seeds.
Notes
Storage: cool within 2 hours, fridge up to 3 days, reheat once until steaming hot all the way through. Swap: soy sauce for tamari (check labels for gluten).