Heat half the oil and fry the tofu until lightly
browned then remove it from the pan.
Heat the
remaining oil and stir-fry the spring onions and
garlic until lightly browned. Add the soy sauce,
sugar and stock and bring to the boil.
Add the
prawns and stir over a low heat for 3 minutes. Blend
the corn-flour and water to a paste, stir into the
pan and simmer, stirring, until the sauce thickens.
Return the tofu to the pan and simmer gently until
heated through.