In a 10 to 12 inch frying pan, mix together jam, Merlot, vinegar, and rosemary until thoroughly combined. Bring to a boil over high heat. Boil until reduced to 1 cup, about 11 minutes.
While cherry mixture boils, cut onions in half crosswise. Thread pork, mushrooms and green onion pieces alternately onto metal skewers (at least 8 inches long), dividing equally between skewers. Lay skewers on a broiler pan; brush tops evenly with about ⅓ of the cherry mixture.
Broil pork about 4 inches from heat until well browned on top, 5 to 6 minutes. Turn skewers over, brush with half of the remaining cherry mixture, and broil until the other side is browned, 2 to 4 minutes.
While pork cooks, bring broth to a boil in a 2 to 3 quart pan over high heat. Add couscous, cover tightly, remove from heat, and let stand until liquid is absorbed and couscous is tender to bite, about 5 minutes.
Spoon couscous onto platter or individual plates and top with skewers. Spoon remaining cherry mixture over skewers.
Notes
Accompany this dish with steamed green beans or sautéed spinach and a glass of Merlot!