Cut the tofu into 1cm slices, and press to remove any excess liquid - you can either use a tofu press if you have one, or just lay the tofu in a single layer between two tea towels, and top with a heavy object for 5-10 minutes.
Add the lemon juice, garlic, red chilli, and a very generous pinch of black pepper to a dish, and mix to combine. Add the slices of pressed tofu, and spoon some of the marinade over the top. Leave for at least 5-10 minutes.
When you're ready to cook, heat a dash of oil in a frying pan, and add the marinated tofu. If possible, try to make sure there are no pieces of garlic left on the tofu, as it may burn in the pan. Cook over a medium heat for a few minutes each side, until crispy.
Pour the excess tofu marinade into a small bowl, and add the cornflour. Mix thoroughly until smooth (obviously lumps of garlic and chilli will remain!).
Pour the lemon sauce over the tofu, along with the vegetable stock. Cook for a few more minutes, stirring carefully (tofu can be a little delicate), until the sauce is thick and sticky. Add the honey or agave, and cook for 1 more minute. Serve warm, topped with fresh coriander (cilantro) if desired.