Mint lovers, prepare yourselves, because the famous green Shamrock Shake is sliding back onto the McDonald's menu starting next Tuesday (February 17th), just in time for St. Patrick’s Day. The seasonal treat blends vanilla soft serve with minty green syrup and whipped topping, a tradition that dates back to 1970. Joining it again this year is the Oreo Shamrock McFlurry, packed with the same mint flavor plus cookie pieces.