Step 1

Heat the oil in a large pan over medium heat. Add the onion and cook for 1 minute until softened. Add the garlic, potato, saffron and wine and simmer for 2 minutes. Add the tomato paste, tomatoes, stock and rosemary and cook for 15 minutes.

Step 2

To make the rouille, place the capsicum, potato, garlic and egg yolk in a food processor and season with salt and pepper. Process to combine, then add the oil in a thin steady stream until a smooth emulsion.

Step 3

Season the stew with salt and pepper, then add the fish and mussels. Cover and cook for a further 5 minutes. Remove the lid and discard any unopened mussels. Serve the stew with toasted baguette and a dollop of rouille on top.