Juice the lime.
Peel and grate fresh ginger.
Peel and crush garlic.
In a large, shallow dish, mix soy sauce, honey, miso paste, lime juice, ginger, garlic, chilli flakes and 2 tablespoons of cold water.
Add the steak and marinade for at least 10 minutes.
Heat olive oil in a large frying pan to very hot heat.
Remove the steak from the marinade and cook for 2 - 3 minutes on each side, depending on thickness. Remove to a plate, cover with foil and keep warm. Keep the marinate to the side.
Peel and finely shop red onion.
Add red onion to the frying pan and cook for one minute.
Add stir-fry vegetables. Quickly cook until tender.