1
First and foremost: this dish lives and dies on the vegetable stock. If you can, make your own. If not, buy the best bouillon you can afford. I used a concentrate called "Better than Bouillon" made by Superior touch. It's very good, and pretty cheap, so that's a good option if you can find it.
2
Heat up the stock in a large pot or wok. You want it to be steaming, but not boiling. This is critical, because if it's too hot, the tofu will break up.
3
Slice up the tofu to about the size of very thick alfredo noodles.
4
Heat the sugar, sesame oil, and soy sauce in a small saucepan, until the sugar melts.
5
Put the tofu slices in the sauce, toss until they're covered in sauce, then dump the entire mixture into the stock.
6
Cook the whole thing for another minute or two, then serve hot right away.