Heat the olive oil in a large Dutch oven or soup pot over medium-high heat. Add the ground beef and cook, breaking it up with a wooden spoon, for 5 to 7 minutes until browned and no pink remains. Drain off any excess fat if needed.

Add the diced onion to the pot with the beef. Cook over medium heat for 3 to 4 minutes, stirring occasionally, until the onion softens and turns translucent.

Stir in the minced garlic, tomato paste, paprika, and dried thyme. Cook for 1 to 2 minutes, stirring constantly, until the tomato paste darkens slightly and the garlic is fragrant.

Pour in the crushed tomatoes and beef broth. Add the bay leaf, salt, and black pepper. Stir to combine and bring the pot to a full simmer over medium-high heat.

Once simmering, add the chopped cabbage and uncooked rice. Stir well, then reduce the heat to medium-low. Cover and cook for 20 to 22 minutes, until the cabbage is tender and the rice is cooked through.

Remove the bay leaf. Stir in the apple cider vinegar. Taste and adjust salt and pepper as needed.

Let the soup rest off heat for 5 minutes. Ladle into bowls and top with chopped fresh parsley if using.