Peel and wash the potato and carrot. Clean and wash the zucchini, tomato and spring onion. Cut potato, carrot and zucchini into small cubes. Cut tomato into quarters, remove seeds and dice flesh. Cut spring onion into thin rings.
Sauté potato, carrot and courgette in 2 tablespoons of hot oil, add stock and blanch for about 2 minutes. Let it cool down. Add diced tomatoes, spring onion rings, remaining oil and vinegar. Season with salt and pepper. Wash the fish, dab dry and cut into pieces. Sprinkle with lemon juice. Season with salt and pepper and turn in flour. Heat the fat in a pan and fry the fish pieces on both sides for 3-5 minutes. Pluck basil leaves from the stalks and cut into strips.
Sprinkle with lemon juice. Season with salt and pepper and turn in flour. Heat the fat in a pan and fry the fish pieces on both sides for 3-5 minutes. Pluck basil leaves from the stalks and cut into strips. Add to the fish and fry briefly. Arrange fish fillets with basil butter and vegetable vinaigrette on four plates