Method:
1 Heat a grill-pan over medium heat, rub the steak with olive oil and season with salt and pepper, cook for 3 minutes each side for medium-rare or until cooked to your liking. Rest for 5 minutes then thinly slice.
2 Combine the fish sauce, lime juice and sesame oil in a bowl, then add the wombok, bean sprouts, herbs, ginger and cashews and toss to coat.
3 Spoon the salad into a bowl and top with the sliced beef to serve.