Rich pork goulash

Name: Rich pork goulash
Ingredients: 500-600g diced pork shoulder or leg; 1-2 tbsp olive oil; 1 red onion, chopped; 1 tbsp flour; 3 tbsp paprika; 1 tsp caraway seeds (optional); 175ml glass of full-bodied red wine; 1 green pepper, sliced; 1 large tomato, roughly chopped; 2 bay leaves; 1-2 tsp balsamic, red wine or cider vinegar; 150ml soured cream, plus extra to serve; pinch of sugar (optional); chopped dill or chives and poppy seeds, to serve (optional); potatoes, rice or buttered pasta (such as tagliatelle), to serve