heat stirring occasionally to keep the pasta from sticking.
Continue to cook until the pasta is fully softened but
retains a slight bites in the center (about 1 minute less
than the package recommends after the pasta reaches a
boil). Drain the pasta, reserving 1½ cups of the cooking
liquid, and return to the pot.
Add the sauce to the pasta and stir to combine, adding
some of the reserved pasta water as necessary to thin the
sauce to the desired consistency. Serve immediately, with
grated Parmigiano-Reggiano.