– 2 Tablespoons olive oil, plus more for the pasta – 2 large leeks, white and light green parts only, thinly sliced, rinsed, and patted dry – 1 lb. mushrooms, sliced (I used a mix of button and crimini) – 3 garlic cloves, minced – 1 cup low sodium chicken broth or veggie broth – 1 cup heavy whipping cream – 1/2 cup shredded Parmesan cheese – 1/4 cup chopped fresh parsley – Salt and pepper, to taste – 1/4 teaspoon crushed red pepper flake – Parmesan, for serving (optional) – 12 oz linguine