Choucroute garni

Name: Choucroute garni
Ingredients: 4 onions, sliced; 200ml white wine; 100ml white wine vinegar; 1 tbsp thyme leaves; 1 star anise; 1 tsp fennel seeds; 1 tsp black peppercorns; 2 carrots, diagonally sliced; 2 celery sticks, peeled to remove the stringy part and cut into 4; 8 garlic cloves; 1 medium Savoy cabbage, cut into 8 wedges; 6 German garlic sausages (or good-quality chipolatas); 400g whole piece of smoked bacon, skin removed and cut into large chunks; 400ml chicken stock; mashed potato, to serve (optional)