1 16-ounce box frozen potato-and-onion pierogi
1 tablespoon olive oil
1 onion, thinly sliced
1 crisp green apple (such as Granny Smith), cut into 1/2-inch pieces
1/2 small red cabbage (about 1 pound), cored and shredded
1/4 cup fresh flat-leaf parsley, chopped
2 tablespoons red wine vinegar
1 teaspoon caraway seeds
kosher salt and black pepper
1/2 cup sour cream (optional)
Cook the pierogi according to the package directions.
Meanwhile, heat the oil in a medium skillet over medium heat. Add the onion and cook, stirring occasionally, until tender, 5 to 6 minutes.
Add the apple, cabbage, parsley, vinegar, caraway seeds, ½ teaspoon salt, and ¼ teaspoon pepper.
Cook, stirring, until the cabbage is slightly wilted but still crunchy, 4 to 5 minutes. Serve with the pierogi and sour cream, if using.