McDonald's classic Shamrock Shake is back with a NEW pal in tow, OREO Shamrock McFlurry! Now serving, this frosty treat blends together McDonald's signature vanilla soft serve with crunchy OREO Cookie bits and green Shamrock McFlurry Syrup. McD's OREO Shamrock McFlurry is creamy, minty and sweet with a chocolate burst you'll be craving long after it's gone. Get one today while supplies last! For a limited time only.