Cut the pork into 3-4 cm cubes. Fry in butter in a pan over medium-high heat until browned, about 5-7 minutes.
Slice the white cabbage into thin strips and finely chop the onion. Place the cabbage strips, sauerkraut, dried mushrooms, bay leaves, juniper berries, and chopped onion into a large saucepan.
Mix the water with the broth cube. Add this mixture to the saucepan along with the browned pork. Bring to a simmer over medium-low heat and stew for 50 minutes, stirring every 5 minutes. Add more water as needed to maintain a stew-like consistency.
Cut the tomatoes and sausage into cubes. Add to the pot and simmer over medium heat for 8-10 minutes.
Stir in the plum jam and tomato paste. Season with salt and pepper to taste. Simmer over low heat for 35 minutes, stirring every 5 minutes and adding water as needed to maintain a stew-like consistency.