Cook the rice according to the instructions on the packet.
Put the parsley, sorrel, chervil, lemon juice and 2 tbsp of olive oil in an oven proof dish and mix together. Season with freshly ground black pepper and add the salmon fillets. Turn the fillets over in the oil mixture, coating the fish on all sides. Cook in the oven for 10- 12 minutes or until cooked - remove and cover with tin foil to keep warm.
While the salmon is cooking, heat the remaining olive oil in a saute pan, add the red onion and cook for 2 minutes. Add the garlic, courgettes, red pepper and cherry tomatoes and cook for 4-5 minutes until the veg starts to soften. Add the capers and cook gently for 1 minute.
Add the cooked rice, parsley and a splash of balsamic vinegar to the cooked vegetables and mix well. Season to taste, adding extra balsamic vinegar if needed.
Place the salmon fillets on top of the rice and vegetables, spoon the remaining olive oil mixture over the top, scatter with spring onions and serve.