Cook bacon in a Dutch oven until just starting to crisp. Remove and drain on paper towels. Cut into halves length-wise and then halves cross-wise. Set aside. Reserve bacon fat in a bowl.
In the same Dutch oven cook sausages until evenly brown, adding a little bacon fat if necessary. Remove and cut into halves length-wise then halves cross-wise. Set aside.
Add a tablespoon of reserved bacon fat back to Dutch oven. Cook onions for 2 to 3 minutes until soft but not brown.
Layer cooked onions, sausages, and bacon at the bottom of the Dutch oven. Season with lots of pepper.
Add leeks, garlic, dried thyme, chopped parsley, and top with a layer of potatoes. Season with more pepper and salt to taste.
Pour in the stock. Cover and bring stock to a boil.
Transfer to a preheated 350°F (180°C) oven for 35 minutes or until potatoes are tender.