Heat 1tbsp of the oil in a flameproof casserole dish and brown the onions for 10 minutes. Add the garlic and mushrooms and cook for a further 5 minutes. Stir in the red wine, chopped tomatoes and stock or water. Add the rosemary sprigs and slowly bring to the boil.
Heat the remaining tablespoon of oil in a frying pan and brown the sausages for 5 minutes, turning them so they are evenly coloured. Transfer the sausages to the casserole, stir them around and season with salt and ground black pepper. Cover with a lid and simmer over a low heat for 40 minutes.
Bring the potatoes up to the boil in salted water and cook for 15-20 minutes. Drain well and return to the pan. Mash the potatoes and beat in the butter, milk and crème fraîche. Stir in the watercress. Taste and season with salt and ground black pepper if necessary.
2tbsp olive oil
3 red onions, peeled and cut into eighths
2 garlic cloves, crushed
200g large flat mushrooms, sliced
150ml red wine
400g can chopped tomatoes
200ml chicken stock or water
2 sprigs fresh rosemary
salt and ground black pepper
8 good quality pork sausages
For the watercress mash:
950g old potatoes, peeled and quartered
25g butter or olive-oil based spread
2tbsp reduced fat crème fraîche
85g watercress, very finely chopped