Half an hour before serving make the tomato and herb salsa by combining all the ingredients then put to one side.
Preheat the oven to 200°C/180°C fan/gas 6.
In a frying pan on a medium heat, stir fry the potatoes for 4-5 minutes in 2 tbsp olive oil, add the vegetables and fry for 2-3 minutes to give them some colour then transfer to a baking dish.
Place the cod loins on top of the potatoes and vegetables, put the sprig of rosemary on top then finish with a sprinkle of Parmesan and a drizzle of olive oil. Bake in the oven for 15-20 minutes.
Just before serving, the sauce can be warmed through or served cold. Divide the cod, potatoes and vegetables between two plates and spoon the salsa on top. Add a lemon wedge to each plate to serve.