Why is Ice Cream used in Hot Buttered Rum?

I don't think I've ever even had hot buttered rum, but I can take a stab at some of your questions:

• 1 part ice cream and 2-3 parts boiling water will still average out pretty hot. If the ice cream is at, say, -20 to -10C, that'll get you in the 60-70C range initially, which is I think fairly normal for hot drinks. And of course, if you keep it in the refrigerator instead, your drink will be hotter!

• I suspect mixing ice cream with butter will help it all mix together better in the end, by helping disperse the fat.

• Ground spices aren't going to need a ton of steeping. I imagine the boiling water would be enough, and if not, the pre-cooking could easily compensate. And since some recipes just have nutmeg sprinkled on top, it sounds like steeping isn't necessarily the goal. If you're really aiming for spiced hot buttered rum, you'll probably want more spices than those recipes, and perhaps to cook them briefly with the butter.

• If you intend to freeze the "batter", including ice cream will help keep it soft enough to scoop/slice. If it were just butter and sugar, it'd get quite hard in the freezer.

• Yes, the milk/cream content of the ice cream would make the drink a little creamier - but I don't know whether hot buttered rum should be a bit creamy. It sounds like it'd be fine either way - personal preference, perhaps?

No Hot Buttered Rum I've ever ordered has involved ice cream, though I'd be interested in trying it out. The original involves only rum, butter, sugar, spices and hot water. I've seen some bars make and keep their own pre-mixed spiced butter with honey, molasses and dark sugar. I guess the ice cream is an extension to that pre-made mixture.

For the purist's Hot Buttered Rum, watch this: http://www.youtube.com/watch?v=t9wNGIgN_f8

I tried the recipe with ice cream this weekend. It was a hit with my guests - we found we didn't particularly want to try the recipe without, as the ice cream seemed to be lending a nice mellowness to the drink that made it particularly palatable to those of us who were not heavy drinkers. It also didn't freeze solid, instead remaining easy to scoop.

I've seen this a lot, too. I'm guessing the ice cream acts as a creamy emulsifier, helping to integrate the fat of the butter without diluting the total fat content or flavor. It also stores at a good consistency in the freezer, and may also help mellow the butter flavor if it seems overpowering.

Here are some additional Hot Buttered Rum recipes to compare. Cheers!