In a large stock pot or Dutch oven, heat the oil over medium-high heat until shimmering. Add onion, carrots, celery, and turnip and cook until softened, stirring occasionally, about 10 minutes.
Stir broth, cabbage, apple, bay leaves, and dill. Bring to a boil. Cover and reduce heat; simmer until vegetables are tender, stirring occasionally, about 30 to 40 minutes.
Remove bay leaves and stir in pickle juice. Season to taste with salt and pepper (I like 1 teaspoon salt and 1/2 teaspoon pepper.) Garnish with sour cream and more fresh dill if desired.
Green apple: A crunchy variety like Granny Smith will hold up nicely as this soup simmers.
Pickle juice: The acidity this lends is what makes this soup recipe so addictive and well-balanced. A splash of fresh lemon juice or red wine vinegar works, too.
Yield: This recipe makes about 6 c. of soup, enough for 4 servings, 1 1/2 c. each.
Storage: Store leftovers covered in the refrigerator for up to 4 days.