Season fish cavities with sea salt and freshly ground black pepper, insert lemon slices and a few sprigs of marjoram, shaved fennel and garlic.
Preheat oven to 200C. Lay fish side by side in a tray lined with baking paper. Scatter tomatoes, olive oil, pour over fish stock. Cover with foil and bake 10 minutes. Remove foil and bake for another 10 minutes on 230C or until cooked nice and brown on top.
Set aside and pour pan juices into a saucepan. Place saucepan on heat and reduce until sauce consistency. Add lemon juice and basil leaves.
Place fish onto a platter and scatter vegetables on the side and pour over sauce. Eat immediately.