In a world of costly prime cuts—stately crown roasts, plump pork chops, and regal racks of lamb—it’s easy to forget about (and steer clear of) the more economical, but less lovable parts of the beast—bellies, brains, cheeks, combs, gizzards, hearts, hocks, kidneys, lungs, marrow, necks, shanks, spleens, tongues, trotters, and, oh yes, testicles.