Melt half of the butter in a large skillet over medium-high heat. Add mushrooms and green onions; sauté until tender, about 5 minutes. Remove from skillet and set aside.
Melt remaining butter in same skillet and add lamb chops; sprinkle with rosemary, garlic powder, salt, and pepper. Sauté until brown on both sides, about 3 minutes on each side; reduce heat to medium and continue cooking until desired doneness is reached, about 5 more minutes for medium. Transfer lamb chops to a platter and hold warm.
Pour red wine into same skillet and cook over medium high-heat, scraping up any browned bits off the bottom. Continue cooking until liquid is reduced by a third. Add reserved vegetables back into pan and heat thoroughly, about 2 minutes; spoon over lamb chops and serve.
Servings: 4