The banana plant is not a tree but the largest known herbaceous flowering plant. The banana leaf consists of the center stalk (petiole) and the blades on either side. The blades have "front" and "back" sides; the "front" side is more glossy than the "back". Mature banana leaves grow to a length of more than two meters. The size of the leaves makes it ideal for wrapping food. Additionally, banana leaves are waterproof and naturally non-stick.

Banana leaves are used as a kind of wrap in Thai cooking (instead of tin foil). Banana leaves not only look beautiful but also lend a subtle aroma and taste when foods are cooked inside them. Banana leaves can be used for barbecuing, baking, or steaming foods. While functioning as a wrapping material, they also lend a hint of flavor to your food that is very pleasant (unlike tin foil or ​parchment paper).

Banana leaf also makes a beautiful background on which to serve various Asian dishes -- excellent for party platters or finger foods.
 

Buying Banana Leaves

Banana leaves are inexpensive to buy -- roughly $3.00-4.00 for a large pack. Buy banana leaves fresh or frozen in large, flat plastic bags at your local Asian supermarket (check the freezer if you can't find them on the shelf or in the produce section).

Storing Banana Leaves

To keep extra leaves for use later, simply wrap up in plastic (a plastic bag will do, secured with elastic), and keep in the freezer. For more on information on culinary uses for banana leaf, see How to Cook with Banana Leaf.

Source: www.thespruce.com