I have had this drink before, but only in its ice cream variation. It's quite delicious, and whenever I drink it, I feel a slight twinge of guilt.
Let's step into the WABAC machine to 2001 or thereabouts. One of my dearest friends was moving away to the West Coast, and I joined her and her wife for a farewell dinner at an Italian steakhouse. As we were entering, we all spied a bartender miserably working a blender to make a grasshopper. The blender was not cooperating, and she (the bartender) was clearly looking forward to being done with the task.
By the end of the evening, we were all feeling more than a little tipsy on Chianti and a wee bit mischievous.
Of the six of us present... five ordered grasshoppers. It was delicious, but I felt terrible for doing that to the bartender as I made the long drive home.
Despite the guilt, it's still a hit, even in this non-ice cream form.