Spinosi's egg-based fettucine, flavored with porcini mushrooms, has a subtly earthy flavor and a natural light-brown color. The Spinosi company, based in Campofilone in the Marche region, produces these fine pastas for discriminating cooks.  Toss tender strands with sweet butter flavored with  fresh sage and a dusting of freshly grated Parmigiano-Reggiano. Like all Spinosi pasta, this fettucini cooks very quickly, in 1 1/2 minutes.