Reduce heat so sauce is at a simmer and cook, stirring occasionally, until sauce is about the consistency of applesauce, 8–10 minutes. Drain, reserving 1 cup pasta cooking liquid (don’t rinse pasta). Step 8Transfer pasta to tomato sauce (it’s okay if some water clings to it) and pour in ½ cup reserved pasta cooking liquid. Cook pasta, tossing constantly with tongs, until sauce clings to each noodle and liquid is mostly absorbed, about 1 minute. Parmesan, finely grated (about ½ cup), tossing constantly until melted into sauce and adding more pasta cooking liquid a couple of tablespoonfuls at a time to loosen sauce if needed.