Drain the tofu, pat dry with a paper towel, and cut into small cubes.
Place the cornflour in a large bowl, take a cube of tofu, coat it in the flour and place on a plate.
Repeat for the rest of the tofu, adding extra cornflour if necessary.
Heat up the oil in a frying pan until hot.
Once the oil is hot, keep it on a medium heat and add the cornflour-coated tofu.
Fry for a few minutes on each side, turning over halfway through (it's easiest to do this using chopsticks). Cook until it’s crispy and lightly browned, but be careful not to overcook, otherwise it’ll become tough.
Transfer the cooked tofu onto a plate lined with kitchen paper (to drain away the excess oil).
For the sauce:
Heat up the oil in a frying pan - you can use the same frying pan you used to fry the tofu.
Add the garlic once hot and fry for a couple of minutes until fragrant.
Add the tamari, sriracha and agave syrup along with the tofu.
Cook for a few minutes, stirring regularly, until the tofu is warmed through and evenly coated in the sauce.
Sprinkle over thinly sliced spring onion and sesame seeds, if desired.
Best enjoyed immediately, but leftovers can be kept covered in the fridge for up to a few days, and can be reheated in a frying pan.
To make this dish spicier, you can add more chilli - either sliced fresh chilli, dried chilli flakes or cayenne chilli powder.
You can also add vegetables - just make sure to make extra sauce if adding extra ingredients.