Gently score the magret duck breast skin in a tight cross hatch pattern, keeping the score 1/8 inch apart and without cutting into the meat. Season both sides with salt and pepper.
Preheat a cast iron pan for 2 min over medium-high heat and cook the magret for 3-5 min on the fat side. When skin is crispy and golden brown, flip on the flesh side and cook for 1-2 min. Then place the magret on a sheet pan and finish cooking in preheated oven (375°F) for 5-6 min. Remove duck from pan and set aside to rest.
Cook potato gratin and green beans by following directions on the packaging.
Heat the veal stock in a pan with the cherry preserve and let it simmer on low for 5 minutes.
Cut the duck magret in slices and place on a plate, add gratin and green beans. Serve with the cherry reduction sauce.CHEF TIPS: Duck Magret is usually cooked like a steak: seared, finished a few minutes in the oven, and served medium rare.