Place the tofu in a freezer bag or dish for marinating.
Combine all the other ingredients except cornflour in a bowl and stir well.
Pour half of the mixture in with the tofu making sure tofu is well covered.
Place tofu in the fridge for at least an hour to marinade. (the longer the better)
Add cornflour and 1 tbsp of the oil to the remaining marinade. Stir well and set aside.
Heat remaining oil in a wok or large pan.
Add tofu and toss over high heat until browned.
Lower to a medium heat and add the rest of the sauce.
Stir occasionally and allow sauce to reduce.
Once sauce has reduced and has become sticky, sprinkle with sesame seeds and lightly toss.
Serve with sliced shallots.