1: Make the marinade: Place the garlic, onion, celery, parsley, cumin, salt, sour orange juice and vegetable oil in a blender and blend to a smooth puree. If you use a food processor, puree the garlic, onion, celery, parsley, cumin, and salt first, then work in the sour orange juice and oil.
2: Pour 1/3 of the marinade in the bottom of a nonreactive baking dish. If using fillets, arrange them on top. If using whole trout, make deep diagonal slits in the sides of each fish. Arrange the fish in the dish. Pour the remaining marinade on top. Marinate the fish, covered, in the refrigerator for 1 to 4 hours, turning the fish once or twice.
4: Set up your grill for direct grilling and heat to high (medium-high if grilling whole fish). Brush and oil the grill grate if not using a fish basket. Place the wood chips on the coals or in your grill’s smoker box.
5: Drain the fish and arrange on the grate (or place in a fish basket on the grate). Grill until browned on both sides and cooked through, 3 to 5 minutes for fillets, 5 to 8 minutes per side for whole fish.
6: Transfer the fish to a platter or plates. Spoon half the garlic sauce over the fish and serve the remainder on the side.
