Put the olive oil in a heavy pot over medium heat. Add the sausage, after removing the casing, and sauté until cooked, stirring occasionally and breaking it into smaller pieces with a spoon. Remove the sausage from the pot with a slotted spoon.

Add the onion and season with salt and pepper. Sauté for about 4 minutes, then add the garlic and continue sautéing for another minute. Reduce the heat and add the tomato paste, stirring constantly and scraping it on the bottom of the pot until it caramelizes and darkens (about 3 minutes).

Add the cabbage, broth, water, orzo, and Parmesan rinds along with a little more salt, and simmer uncovered for 10 minutes, stirring frequently. Return the sausage to the pot and cook for another 5-8 minutes, stirring occasionally, until the cabbage and orzo are tender. Remove the Parmesan rinds.

At the end, add the parsley and vinegar. Check the seasoning and serve in bowls with country-style bread and grated Parmesan.