Here’s a grown-up version you can make at home.
1 ¾ cups low-fat vanilla ice cream
¼ cup vanilla vodka (or unflavored vodka + ½ tsp. vanilla extract)
¼ cup Crème de Menthe
½ tbsp grated dark chocolate + 1 tsp for topping
A few sprigs of mint
Throw ice cream, vodka, and crème de menthe in a blender and mix until it’s just evenly combined. Make sure not to over-blend. If you do, just add more ice cream.
Here's some background history to the McDonald shake:
The Shamrock Shake was developed in 1970, according to McDonald’s. It was created to raise money to buy the four-story house which would become the first Ronald McDonald House.
When Philadelphia Eagles tight end Fred Hill's daughter was diagnosed with leukemia and began treatment, the family had to camp out in the hospital waiting rooms in hospitals. They saw other families doing the same and realized that many families traveling long distances to visit sick family members needed a place to stay.
Hill and his team decided to raise funds for the project. Jim Murray, the team’s general manager, called a friend who worked on McDonald's advertising and suggested the team take part in the next promotional push. It just happened to be St. Patrick's Day.
Rogers Merchandising in Chicago created the drink, with James Byrne, the executive artist at the firm, using a family recipe for the shake.