Heat a large, wide-based pot over medium heat. Add 2 teaspoons neutral high-heat cooking oil, like canola, rice bran or grapeseed oil. When the oil is shimmering, add the sausage and brown on one side, about 3 minutes. Turn and brown another side, 2 to 3 minutes. Turn and brown another side if possible, about 2 minutes. Remove from the pan.
Add the apple, onion and cabbage to the pan, scraping the bottom of the pan with a wooden spoon as the water releases from the vegetables. Cook until wilted, stirring occasionally and reducing the heat to medium-low as needed, about 10 minutes. Add the vinegar, 1/4 cup water (or broth for added flavor, if you have some) and 1/4 teaspoon each salt and pepper. Place the sausage on top. Partially cover and simmer until the fruit and vegetables become wilted and are fork-tender, about 5 minutes. Slice the sausage on a cutting board and serve over the fruit and vegetables.