Scrub and pat dry mussels.
Mince onion and garlic, set aside.
Bring a stock pot with a pinch of salt to a boil and add the dry pasta, cook until al dente.
Wash parsley and rough chop; set aside.
In a large skillet, add olive oil, minced garlic and onion; heat for about 2 minutes until fragrant.
Add in 1 cup of dry, white wine and stir.
Add in scrubbed mussels, and parsley and stir. Cooked covered for about 3 minutes over medium heat.
Mussels will begin to open up. Stir to combine flavors and simmer for another 2 minutes.
Once mussels are all opened, transfer them to another dish.
Carefully drain half the liquid only from the pot and reserve the onion, garlic, and 50% of the wine mixture.
Add in the full can of tomatoes and mix; simmer over low heat.
Meanwhile, remove 50% of the mussels from their shells and add them to the sauce, leave the other half on the shell.
Drain pasta water if you have not and add the pasta to a serving dish or cast iron pan.
Carefully pour sauce on top of the pasta, and add the shelled mussels.
Sprinkle with additional parsley and enjoy warm.