Someone somewhere undoubtedly has already made this recipe.  But it came to me out of the blue this evening, and I enjoyed it very much:

3 large scoops of chocolate ice cream
1 cup of milk, give or take
1 very heaping teaspoon of Ghirardelli cocoa powder
1-2 shots of 18 year scotch (I prefer Glenlivet), to taste*

*The key is not to overpower the milkshake but to accent it.

Blend.
Serves 1-2 people.