Heat the oil in a wok set over a medium-high heat. Once hot, add the curry paste and stir-fry for about one minute, until fragrant.
Gradually stir in half the coconut milk and cook for about one minute, until the oil from the paste rises to the surface of the coconut milk. Once this happens, stir in the remaining coconut milk, then mix in the palm sugar and soy sauce and cook for a further minute.
Bring the mixture to the boil, then add the tofu. Reduce the heat and simmer for 2–3 minutes, until the tofu is heated through.
Stir in the sweet basil, lime leaves and sliced chilli. Remove the pan from the heat.
Serve the curry immediately, with a bowl of rice, garnished with extra basil leaves.