Clean and shell 16 tiger prawns, set aside and reserve the shells.
Blanch 6 scored tomatoes in a large saucepan of boiling water until the skin splits, refresh, peel, remove seeds, coarsely chop flesh and set aside.
Heat ¼ cup (60 ml) olive oil in a large saucepan over medium heat; add 2 finely chopped onions, 6 finely chopped cloves of garlic and 2 sprigs each of thyme, oregano and basil and 1 fresh bay leaf and sauté until onion softens.
Increase heat to high, add the shells of the prawns and a pinch of saffron and stir occasionally until the shells turn pink.
Add the chopped tomato and 4 cups (1L) water and simmer gently for 30 mins until infused. Strain through a fine sieve into a clean saucepan, pressing on solids to extract liquid; solids can now be discarded.
To the stock, add 4 tsp (20 ml) brandy and 1 tin (380g) NESTLÉ IDEAL EVAPORATED MILK, season to taste and keep warm.
Return stock to low simmer and add 600g trout cut into 3 cm pieces, 12 shelled green Norwegian mussels and the prawn meat, and stir occasionally until just cooked through. Season to taste.
To serve, remove the fish, prawns and mussels from the stock and place in bowls.
Pour over the stock and garnish with a sprig of parsley and a sprinkling of lemon zest.