Cook the Pasta: Bring a pot of salted water to a boil. Add the pasta and cook until just firm (al dente). Drain and keep a small amount of the cooking water aside.
Prepare the Mussels: Rinse the mussels under cold water. Scrub the shells clean and pull off the beards. Throw away any mussels that stay open when you tap them, as they are not safe to eat..
Make the Sauce: In a large pan, heat olive oil. Sauté the garlic (and onion if using) for 1–2 minutes until soft and fragrant.
Add Tomatoes and Liquid:Add the tomatoes and cook for 3–4 minutes until they soften. Pour in seafood broth or your non-alcoholic wine substitute and let it gently simmer.
Cook the Mussels: Add the mussels to the pan, cover with a lid, and let them steam for 5–7 minutes until they open. Throw out any that don’t open.
Mix with Pasta: Add the cooked pasta to the sauce. Gently toss everything together. Use a bit of reserved pasta water to loosen the sauce if needed.
Finish and Serve: Taste and adjust with salt, pepper, and chili flakes if desired. Garnish with chopped parsley and add lemon wedges on the side before serving.