Bring a large pot of well-salted water to a boil. Cook pasta according to package instructions until al dente. Reserve 1 cup of pasta water before draining.
12 ounces pasta
While the pasta cooks, rinse mussels under cold water and scrub the shells. Remove any beards and discard any mussels that are open and do not close when tapped.
2 pounds mussels
In a wide skillet over medium heat, melt butter with olive oil. Once the butter foams, add minced garlic and shallots. Cook for about 2 minutes, just until fragrant — do not brown.
3 tablespoons unsalted butter, 2 tablespoons olive oil, 3 cloves garlic, 2 shallots
Add white wine, chicken broth, lemon juice, parsley, red pepper flakes, salt, and pepper. Stir to combine.
3/4 cup dry white wine, 1/2 cup low-sodium chicken broth, 1/4 cup parsley, 1 teaspoon red pepper flakes, 1/4 teaspoon kosher salt, 1 lemon, juiced, 1/4 teaspoon freshly cracked black pepper
Add the cleaned mussels to the pan. Cover and simmer over medium-high heat for 5 minutes, or until the shells have opened. Discard any mussels that remain closed.
2 pounds mussels
Add the drained pasta directly to the pan. Toss to coat, cover, and simmer over low heat for 3 to 5 minutes. Finish with freshly grated parmesan and chopped parsley.
12 ounces pasta