Combine all of the ingredients in the blender and pulse until completely smooth.
Divide the milkshake mixture among glasses and top it off with some whipped cream if you wish.
Video
Notes
Dairy Free/ Lactose Free Alternative - use plant based or lactose free vanilla ice cream as the base. I recommend oat milk ice cream because it is creamy, rich, and usually nut-free. As far as milk, use a milk alternative like oat milk or almond milk. Or, to make it simply lactose free, use lactose free whole milk.
Topping options: Whipped cream, cherries, green and/or orange sprinkles, chocolate shavings, chocolate syrup, green decorating sugar, thin mint cookies (crushed).