3 tablespoons olive oil, divided
4 small lamb loin chops (1 pound)
Kosher salt and freshly ground pepper
1/2 medium shallot, finely chopped (about 2 tablespoons)
2 tablespoons brown sugar
1 teaspoon red-wine or sherry vinegar
1 pound rhubarb stalks, sliced into 2-inch pieces
1/4 cup golden raisins
1/2 cup crushed walnut pieces
2 tablespoons roughly chopped fresh parsley