Meat lovers tired of mass-produced, machine-cut supermarket lamb chops and chicken breasts are in luck. The corner butcher shop is back — and this time with a sustainable slant. Around the country, small-scale butchers are hanging out their shingles, offering local, grass-fed and organic meats cut on the premises. One example is The Meat Hook in Brooklyn, which sells everything from London broil to homemade gourmet sausages, all from livestock raised on small, sustainably operated farms in upstate New York. Avedano’s Holly Park Market in San Francisco offers similar fare and even runs butchering classes for those who want to slice their own pork ribs and porterhouse steaks.