Step 1

Roast the onions

Step 2

Preheat an oven to 350°F. Rub a shallow baking dish with a little olive oil. Spread the onions in an even layer in the dish and season lightly with salt. Roast, stirring once or twice, until softened and just beginning to brown, about 20 minutes.

Step 3

Season the fish

Step 4

Meanwhile, cut the chilies in half lengthwise, then finely chop the flesh. Place the chopped chilies in a small bowl, add the adobo sauce and stir to form a paste. Place the fillets on a plate, season lightly on both sides with salt and then rub both sides with the chili paste.

Step 5

Cook the fish

Step 6

Arrange the fillets, bone side up, on top of the onions. Bake until the fillets begin to flake apart near the tail ends, 6 to 9 minutes depending on thickness. Squeeze the juice from the lime halves over the fillets and onions, garnish with the cilantro and serve. Serves 4.

Step 7

Adapted from Williams-Sonoma Food Made Fast Series, Seafood, by Jay Harlow (Oxmoor House, 2007).