Yesterday I made a dish that required cooking in banana leaves, so I looked up exactly how to do it. It was fairly easy.
You can buy frozen banana leaves at Asian and Latin markets in the US. They are usually in the same area where they have other wrappings (eggroll skins, empanada shells, etc.). Each package seems to have one leaf, but these are huge so you probably won’t need more than one. They cost about $1-$1.50. After you buy it, keep the banana leaf frozen until ready to use.
When you’re ready for it, boil water in a wide saute pan or similar. Take the banana leaf out of the package and put it in the pan – if it doesn’t fit (and it won’t, unless you have a HUGE pan, just put one side of it, and keep moving it until the whole thing defrosts. Alternatively, if you have a large enough pan to fit the banana leaf, just pour boiling water on it and keep it there until it defrosts. You want the banana leaf to be flexible.
Cut off the center rib of the leaf with a knife and discard.
Then tear the leaf into sections large enough to roll your packet in. Make it be about 5-6 times as large as the food you put inside it. Then roll it like you would a burrito: roll it once, fold in the top and bottom corners and continue rolling it. Secure it with kitchen string.