Soupe de poisson, rouille and Gruyère

Begin by making the fish soup. Ensure the fish have been thoroughly scaled and cleaned, then drain in a colander and place into a bowl with the saffron, cayenne and half of the olive oil. Place the bowl in the fridge and leave to marinate overnight

Remove the marinated fish from the fridge and drain, using a colander placed over a bowl to retain the liquid from the fish. Heat 1 tbsp of olive oil in a large frying pan and fry the fish until golden

Meanwhile, place a large saucepan on the hob until it gets very hot, then add the remaining tablespoon of olive oil. Fry the carrot, celery, fennel, garlic, onion and leek until they’re golden brown in colour

Add the Armagnac and Pernod to the pan, setting the alcohol alight with a match - take care at this stage as the flames may flare up quite high. Add the plum tomatoes and tomato purée, stir well and cook for 5 minutes on a medium heat. Add the fried fish, drained marinade, stock and diced potato and bring the soup to the boil. Reduce the heat and leave to simmer for 90 minutes

Once the soup has simmered, pour into a blender or food processor and blitz until smooth, including the fish bones. Pass the blended soup through a fine sieve into a clean pan, season with lemon juice and salt to taste and set aside until serving

To make the rouille, combine the egg yolk, harissa, saffron and garlic in a food processor, slowly adding the pomace oil (as if making a mayonnaise). Add the mashed potato to the rouille mixture, blend until smooth, and then gradually mix in the vegetable oil in the same manner. Season to taste with salt and lemon juice, adding a little warm water if the consistency is too thick

Preheat the oven to 180°C/gas mark 4

For the croûtons, slice the baguette into 2mm thick pieces and place the slices onto a baking tray. Drizzle over the olive oil and bake for approximately 7 minutes - the croûtons should be crisp and golden in colour when ready

To serve, reheat the soup if necessary and serve in bowls, along the with rouille, croûtons and grated Gruyère