Pork Chops Marsala

boneless pork loin chops, 1/2" thick (4 oz each), trimmed of fat

salt and freshly ground pepper

olive oil, divided

package (8-10 oz) sliced cremini or white mushrooms

large (1/4 cup) shallot, chopped

dried thyme or 1-1/2 teaspoons fresh thyme leaves

chicken broth

Marsala wine

cornstarch