Strain the rice and place it in a hot wok or saucepan. Stir in the coconut milk, salt and sugar. Bring to a simmer and cook for 4-6 minutes, or until the coconut milk has been absorbed and the rice is thick and sticky. Stir in the oil, then transfer the mixture to a tray and cool for 5-10 minutes. Soften the banana leaves, either over a gas fire, in a hot frying pan, or by steaming or microwaving them for a few minutes. Lay a banana leaf on the bench. Place one heaped tablespoon of the cooled rice in the centre of the leaf. Next add a single piece of banana, followed by of tablespoon rice on top of the banana – the banana should be sandwiched between the rice. Now fold the sides of the leaves over, as you would a parcel.
Repeat with the remaining rice, banana and banana leaves. If you have softened the leaves properly, you won’t need to use anything extra to secure the parcels.
Half-fill a large steamer, wok or saucepan with water and bring to a rapid boil over high heat. Place the parcels in your steamer basket, seam side down, and set it over the pan of water. Steam for 30 minutes.
Enjoy the sticky rice cakes hot.