Ingredients for 6 servings

servings
  1. 1 pork wheel (fresh ham slice with central bone) weighing 1.8 kg (4 lb)
  2. 800 g (28 oz) sweet onions, thinly sliced (Roscoff style)
  3. 8 cl (0.3 cup) good alcohol vinegar
  4. Salt and freshly ground pepper
  5. A little butter and oil