If you can’t get banana leaves, foil will do just fine, though it’s nowhere nearly as pretty.
1 to 2 pounds fish (firm flesh, like tilapia)
2 stalks of lemongrass
1 garlic clove
1/2 birds eye chili (if you cannot get the chili peppers used in Thai cuisine, a Serrano pepper will do, use only a bit of it.)
1/2 teaspoon salt
1/2 teaspoon pepper
1/2 teaspoon sugar
2 teaspoons vegetable oil
Peel lemongrass and remove stalk. Cut into very thin strips and put into mortar. Cut shallots, garlic and chili into small pieces and add to mortar. Add salt, pepper and sugar, and pound mixture with pestle until finely ground. Add oil.
Tear off a square sheet of foil. Rinse fish, and lie in center of foil. Spoon mixture over fish, and then fold sides of foil to the center to make a packet. Seal the edges together as well. Put on a hot grill pan or barbecue about 10 minutes, or until fish flakes easily.