Heat the oven to 200C/400F/Gas 6. Roll the hoki in the beaten egg, then in the breadcrumbs and then in the mixed chopped herbs. Pat with hands to secure the herbs.
Heat the olive oil and pan fry the fish for two minutes on each side. Place on a baking tray in the oven and roast for five minutes or until cooked through.
To make the sauce, heat the oil, add the shallot and garlic and cook gently for two minutes. Add the sweet potato and cook for another minute, stirring well. Add the Brie and double cream, stir to combine and season well. Cook for two minutes.
To serve, place the hoki on a plate and spoon over the sauce.