Put a 10-inch straight-sided saute pan over medium heat for 5 minutes. Toss the lamb with the vegetable oil in a medium mixing bowl. When the pan is hot, sear the lamb for 1 minute on each side. Remove to a plate and cool for 3 to 4 minutes. Add the meat to a 1-gallon resealable plastic bag, then pour in the 16 ounces of wine and 4 rosemary sprigs. Remove as much air as possible so that the wine is completely surrounding the meat. Put the bag in a container to prevent leaks and refrigerate for 3 hours.
Heat the oven to 250 degrees F.
Transfer the contents of the bag back to the 10-inch straight-sided saute pan and cover. Put the pan on the middle rack of the oven and braise until the meat is tender and falling away from the bone, about 3 1/2 hours.
Remove the meat from the oven to a platter. Discard the rosemary. Cover the meat with aluminum foil to keep warm while finishing the sauce.
Pour the pan juices into a gravy separator and allow it to separate before pouring 2 cups of the liquid back into the pan. Set the pan over medium-low heat and add the dried plums and apricots. Simmer, whisking frequently, until the sauce has reduced and thickened slightly, about 10 minutes. Whisk in the butter 1 piece at a time, adding another piece only after the previous piece has melted. Whisk in the remaining 1 tablespoon of wine and the remaining chopped rosemary and continue to cook for another minute. Taste and adjust seasoning by adding salt and pepper, if needed.
Pour the sauce over the meat and serve immediately.