Put the orzo and 2-1/4 cups of the stock in a microwave-safe container. Cover and cook in a microwave oven on high power for 11 minutes. Keep covered until ready to serve. (Or bring 2 cups of the stock to a boil in a covered saucepan. Add the orzo, stir, cover, and return to a boil. Reduce the heat to low and simmer for 10 minutes, or until the stock has been completely absorbed.)

Meanwhile, put the oil in a large, heavy skillet over high heat. Season the chops with salt and pepper. Add the chops to the skillet and brown on one side for 2 minutes. While the lamb cooks, peel the garlic. Drop it and the anchovy fillet down the chute of a food processor with the motor running. While the anchovy and garlic purée, peel and quarter the onion. Stop the motor and scrape down the sides of the bowl with a rubber spatula. Add the onion and pulse just until coarsely chopped.

Turn the lamb and brown for 2 minutes on the other side while you coarsely chop the olives. Chop the fresh rosemary. (If using dried rosemary, crush the leaves between your fingers.) With a wide spatula, remove the chops to a large platter in one layer. Pour out half the fat from the skillet. Add the garlic, anchovy, and onion and sauté for 2 minutes. Add the olives, rosemary, capers, and salt and pepper to taste. Mix well.

Spoon an equal amount of the vegetable mixture on top of each chop. With a wide spatula, slide the chops back into the skillet with the vegetable mixture on top. Add 1/2 cup of the remaining chicken stock (1/4 cup will be left over if you're cooking the orzo on the stove). Cover and cook for 2 minutes over high heat. Reduce the heat to medium and cook for 2 more minutes. Serve the chops on individual plates with the cooked orzo on the side and the pan juices drizzled over both.