Cut the tofu into 4 'steak' shapes. Use a clean tea towel or some kitchen paper to squeeze as much liquid out of each piece of tofu as you can (or you can use a tofu press, if you have one).
Place the tofu pieces in a dish, and drizzle with half of the soy sauce. After a couple of minutes, turn the pieces over, and drizzle the remaining soy sauce on the other side. Leave to marinate for a few minutes.
Mix all of the spices thoroughly on a small plate.
When the tofu has marinated for a few minutes, press each piece into the spice mixture, on both sides.
Heat the oil in a frying pan, and add the coated tofu steaks. Cook over a medium heat for 5 minutes or so on each side, until the spices are a deep brown colour and the tofu is beginning to crisp up. Best served immediately.
If you'd like to prepare these vegan steaks in advance, just marinate the tofu and coat it in the spices, then store it in the fridge for a day or so, and cook just before serving.