Heat oil in a large frying pan over a medium heat. Add onion and cook for 8 minutes or until soft, stirring occasionally. Add garlic and cook, stirring for 2 minutes longer. Add Polpa, wine, dried herbs, chilli flakes and pepper and stir to combine. Simmer 20 minutes or until thickened, stirring occasionally.
While sauce is simmering, cook spaghetti as directed on packet.
Add Marinara mix and mussels to sauce. Cover and simmer 4 minutes or until seafood is cooked. Discard any unopened mussels. Add half the parsley and stir to combine. Serve sauce over pasta and top with remaining parsley.