1. Preheat the oven to 220 degrees Celsius.
2. Peel and thinly slice the carrots. Cut the pepper and spring onion thinly lengthwise.
3. Make the sauce by putting the curry paste, vegetable stock and coconut milk in a pan and bringing to the boil. Season with soy sauce.
4. Put the sliced vegetables and the frozen or fresh spinach in an oven-proof dish. Cut each cod fillet into 3-4 pieces.
5. Place the cod pieces on top of the vegetables in the dish then pour over the curry sauce. Bake in the oven for approximately 18-20 minutes until the fish is cooked through.
6. Serve as is or along with rice or noodles.