- canola oil, for the foil or griddle
- 1 teaspoon finely grated orange zest
- 3/4 teaspoon fennel seeds, crushed
- pinch saffron (about 1/8 teaspoon)
- kosher salt
- 1 3-pound piece boneless, preferably skin-on mahimahi or halibut fillet
- grilled orange, for serving (optional)
- Prepare the grill. Lay a double layer of 12-by-16-inch foil or a griddle on top of the grate. Just before grilling, oil the foil or griddle.
- Combine the orange zest, fennel seeds, saffron, and 1 teaspoon salt in a small bowl. Season the fish with the spice rub. Place the fish, skin-side down, on the foil or griddle. (The skin will help shield the flesh from overcooking or drying out.) Cook, covered, until opaque throughout, 20 to 25 minutes.
- Transfer the fish to a serving platter. Serve with the grilled orange, if desired.