Cider-Braised Pork Shoulder

pork shoulder roast, cut into 3- or 4-inch chunks

Kosher salt to generously season pork

vegetable oil

large onion, chopped

salt, plus more to taste

freshly ground black pepper

fresh sage leaves, torn

bottle hard apple cider

apple cider vinegar

creme fraiche or heavy cream

cayenne pepper

Creme fraiche for garnish

Chopped fresh chives for garnish