Heat the butter in a large Dutch oven or heavy-bottomed pot over medium heat until melted and bubbling.

Add the sliced kabanos sausages and cook for about 4-5 minutes until they begin to brown and release their smoky fat.

Toss in the sliced onions and cook for another 5 minutes, stirring occasionally, until they become soft and translucent.

Add the sliced red cabbage, diced apple, and whole rosemary sprigs to the pot, stirring well to coat everything in the flavorful fat.

Pour in the apple cider vinegar and vegetable broth, then sprinkle with brown sugar, salt, and black pepper.

Reduce the heat to low, cover the pot with a tight-fitting lid, and simulate a braise by cooking gently for 35 to 40 minutes.

Stir the mixture occasionally to ensure even cooking, adding a splash of water if the pot looks too dry.

Once the cabbage is tender but not mushy, remove the lid and increase the heat to medium for 2-3 minutes to evaporate any excess liquid.

Discard the rosemary stems, taste and adjust seasoning if needed, and serve warm alongside your main course.