Rajas is the Spanish word for "strips," and in the Mexican kitchen it generally refers to strips of chile.

　　Active time: 1 1/4 hr Start to finish: 1 1/2 hr

　　

Ingredients

Makes 8 servings

　　

For rajas

1 1/2 lb fresh poblano chiles

　　1 1/2 lb white onions, halved lengthwise, then sliced lengthwise 1/4 inch thick

　　3/4 teaspoon salt

　　3 tablespoons safflower oil

　　

For fish packets

1 lb banana leaves*, thawed if frozen

　　8 (6-oz) pieces skinless snapper or halibut fillet

　　1 cup crema (thick Mexican cream) or crème fraîche plus additional for drizzling if desired

　　Garnish: fresh cilantro leaves

　　

Make rajas:

Step 1

Roast chiles on racks of gas burners over high heat, turning with tongs, until skins are blackened, 10 to 12 minutes. (Or broil chiles on a broiler pan about 5 inches from heat, turning occasionally, about 15 minutes.) Transfer to a large bowl and cover tightly with plastic wrap, then let stand 20 minutes.

　　

Step 2

When cool enough to handle, peel chiles, discarding stems and seeds (do not rinse under running water as this washes away flavor), and cut lengthwise into 1/4-inch-thick strips.

　　

Step 3

Cook onions with salt in oil in a 12-inch heavy skillet over moderate heat, stirring, until onions are tender but still have texture, about 10 minutes. Stir in chiles and cook, stirring, 1 minute, then season with salt.

　　

Assemble fish packets:

Step 4

Preheat oven to 450°F.

　　

Step 5

Unfold banana leaves. Cut off (and reserve) tough center rib that runs along bottom edge of each leaf with kitchen shears. Cut ribs into 12- to 14-inch strips for tying packets. Gently cut leaves into 8 (12-inch) squares, being careful not to split them.

　　

Step 6

Slowly run a banana-leaf square across flame of a gas burner, just enough to "melt" outer coating on leaf (it will become quite shiny; if you have an electric stove, hold leaf slightly above burner on moderately high). Place a piece of fish in center of square and season with salt, then top with 1/2 cup rajas and 2 tablespoons crema. Fold 2 sides of banana leaf over fish to enclose it, then fold in opposite sides to form a packet. Tie packet with a strip of banana-leaf rib and transfer to a large baking sheet. Assemble 7 more packets in same manner.

　　

Step 7

Bake fish packets in middle of oven 20 minutes, then transfer each to a large plate or shallow soup bowl. Cut ties of packets and open them (leaves are not edible). Drizzle fish with additional crema.

　　

Step 8

Available at Latino and Asian markets.