- Preheat the grill, setting the burners to medium. Oil the grate.
- In a bowl, combine the oil, lemon zest and juice, thyme, garlic and red pepper flakes. Season with salt. Set aside half of the marinade in a small bowl until ready to serve.
- Add the fish to the bowl of remaining marinade and toss well to coat. Let marinate for 10 minutes.
- Thread the tomatoes onto four metal or wooden skewers (which have been soaked in water for 30 minutes). Place on a plate. Brush lightly with oil. Season with salt and pepper.
- Grill the tomatoes for 5 to 6 minutes or until slightly charred, turning them over halfway through cooking. At the same time, grill the fish for 2 minutes on each side or until the desired doneness (see chef’s tip).
- Divide the spinach among four plates. Top with the fish and tomatoes. Drizzle with the reserved marinade.
Chef’s tip : Depending on the size and thickness of the halibut fillets, the cooking time may vary slightly. Instead of halibut, you can ask your fishmonger for a firm white-fleshed fish that will stand up well to the heat of the barbecue.