Begin by cleaning the mussels thoroughly under cold running water. Scrub the shells and remove any beards with your fingers or a knife.

In a large pot or deep skillet, heat the olive oil over medium heat. Add the chopped onion and sauté until it becomes translucent, about 5 minutes.

Stir in the minced garlic and cook for an additional 1-2 minutes until fragrant, being careful not to burn it.

Add the crushed tomatoes, red pepper flakes, oregano, basil, salt, and pepper to the pot. Stir everything together and let it simmer for about 10 minutes to allow the flavors to meld.

Carefully add the cleaned mussels to the pot, stirring gently to coat them in the sauce. Cover the pot and cook for about 5-7 minutes, or until the mussels have opened. Discard any mussels that do not open.

Once the mussels are cooked, sprinkle with fresh parsley and give it a gentle stir.

Serve the mussels hot, with lemon wedges on the side for squeezing over the top. Enjoy!