Step 1
To make the steak marinade, combine the dark soy sauce, neutral oil and brown sugar in a mixing bowl and stir to combine. Brush the marinade onto both sides of the steaks and leave them to come to room temperature. Heat a charcoal or gas grill, or an indoor grill pan, to a medium-high heat in preparation for cooking the steaks.
Step 2
Bring a pot of water to the boil and add the noodles. Boil for 2 minutes, then drain and rinse under cold running water and set aside to continue draining while you prepare the rest of the salad ingredients.
Step 3
To make the dressing, use a large mortar and pestle, preferably, or a food processor. Combine the garlic and the bird’s eye chillies and crush to form a smooth paste. Add the sugar and crush in the tomatoes. It needn’t be completely smooth: a few chunks are OK. Transfer to a mixing bowl and add the lime juice, fish sauce and neutral oil. Stir to combine.
Step 4
Rinse the red onion slices under cold running water and then add them to the dressing. Set aside.
Step 5
Use a rolling pin or a heavy mallet to break apart the cucumber – you want irregular, bite-sized pieces – and set aside.
Step 6
Finely chop half of each quantity of the herbs, leaving the rest for the salad garnish.
Step 7
Cook your steaks for 2-3 minutes per side or to an internal temperature of about 55C-58C medium-rare. Cook for longer if you like them well-done and allow to rest for 5 minutes before slicing very thinly.
Step 8
In a large mixing bowl, combine the noodles, dressing, cucumber and chopped herbs and toss to combine. Lay this on the base of a large platter or on individual plates. Place the sliced steak on top. Garnish with the spring onions and the remaining fresh herbs, and serve.