1. Place the beef in a medium-sized saucepan. Add sufficient water to cover and bring to a boil. Lower the heat and simmer for 1-1¼ hours, or until the meat is tender, skimming the liquid occasionally. Remove the beef slices with a slotted spoon and set aside.

2. Heat the oil in a saucepan over moderate heat. Add the red curry paste and stir-fry for 1 minute. Stir in 2 tablespoons of coconut milk and cook, stirring constantly, for 5 minutes.

3. Add the cooked beef slices to the saucepan together with the fish sauce, sugar, the remaining coconut milk and lime leaves. Bring to a boil, then lower the heat and simmer, stirring occasionally, for 15 minutes.

4. Wearing gloves if possible, slice the chilies into thin rounds and remove the seeds. Just before serving the curry, stir in the sliced chilies and the sprigs of basil.