Heat olive oil in a large pot over medium heat.
Add diced onion and cook 5–7 minutes until soft and lightly golden.
Add ground beef to the pot.
Break it up with a spoon and season with salt and black pepper.
Cook 6–8 minutes until fully browned and no pink remains.
Drain excess grease if needed.
Stir in diced tomatoes with their juice.
Add tomato sauce if using.
Pour in beef broth.
Add Italian seasoning and bay leaves.
Stir well to combine.
Add chopped cabbage and gently press into the liquid.
Bring to a gentle boil.
Reduce heat and simmer 25–35 minutes until cabbage is tender.
Remove bay leaves.
Taste and adjust seasoning if needed.
Garnish with fresh parsley and serve.