Frozen banana leaves are available at Asian markets, but keep in mind that they’re inedible. I didn’t use them for this recipe but they’re fun to work with. Cut out four 10” x 12” rectangles. Wipe them off and season with salt and curry powder. With 1 long edge of each rectangle facing you, lay a layer of rice and curry mixture on top lengthwise and in the center of each (about 1 ½ inches from bottom). Fold short sides of rectangle over mixture. Tie with twine if desired (don't worry if leaves tear). Place in bamboo steamer and steam in a large pot of boiling water (1-2 inches deep) for 2 minutes to seal in the flavors.