4 teaspoons chili powder, preferably made with New Mexico or ancho chiles (see Note)
2 tablespoons lime juice
2 tablespoons extra-virgin olive oil
1 teaspoon ground cumin
1 teaspoon onion powder
1 teaspoon garlic powder
1 teaspoon salt
1/2 teaspoon freshly ground pepper
2 pounds mahi-mahi or Pacific halibut (see Note), 1/2- 3/4 inch thick, skinned and cut into 4 portions
To prepare fish: Combine chili powder, lime juice, oil, cumin, onion powder, garlic powder, salt and pepper in a small bowl. Rub adobo rub all over fish. Let stand 20 to 30 minutes for the fish to absorb the flavor.
Preheat grill to medium-high.
Oil the grill rack (see Tips) or use a grilling basket.
Grill the fish until it is cooked through and easily flakes with a fork, 3 to 5 minutes per side. Transfer the fish to a platter and separate into large chunks.
Mahi-mahi (also called dorado) from the U.S. Atlantic and halibut from the Pacific are both sustainably fished and considered best choices for the environment. For more information, go to seafoodwatch.org.
Mildly spicy dried chiles, such as ancho or New Mexico, add moderate heat and rich flavor to Mexican sauces like mole. Chili powder made from these chiles has more flavor than American-style blends. Look for whole dried chiles in the produce section of large supermarkets and New Mexico or ancho chili powder in the specialty-spice section of large supermarkets or online at penzeys.com.