1. Remove and discard the seeds from the dried red chillies, then soak the chillies in hot water for 15-30 minutes.
2. Grind together the softened chillies, ginger, garlic and szechwan pepper to make a smooth paste.
3. Heat the oil in a pan, then add the minced shallots and fry them until they start to soften. Add the reserved paste and fry for 2 minutes, stirring.
4. Now add the remaining ingredients – tomato paste, soy sauce, mirin, tomato ketchup, 5-spice powder and sugar – and stir well. Add water as required to make a fairly thick paste and cook the sauce for 5 minutes. Taste it to see that the flavours are balanced – you can add soy sauce or vinegar (or more mirin) as per your taste.
Heat the oil over high heat in a wok, then add the sliced onions and stir-fry for a minute until the onions soften. Now add the pepper strips and the sliced steak, and continue to stir-fry until the steak is almost cooked. This should take 2-3 minutes. Stir in the szechwan sauce to taste and let the mix simmer gently for 2 minutes. Serve hot over plain steamed rice garnished with sliced spring onions.