Heat 2 tbsp of olive oil in a casserole and fry the sausages for 10 minutes until well browned. Remove and set aside.
Add cabbage, apple, mustard, cider, and vinegar to the pan, bring to a simmer, season, and return sausages with juices. Cover and simmer for 1½ hours.
Preheat oven to 200°C (fan 180°C, gas 6). Boil potatoes in salted water for 15 minutes, drain, then toss with remaining oil and seasonings. Roast for 45 minutes until crisp.
Serve sausages with braised cabbage and crispy potatoes, garnished with chopped parsley.
Notes
Use high-quality wild boar sausages for best flavor.