Ferran Adria made foams famous, but Indians may have beaten him to it by a few hundred years.
Many years ago, my cousin was posted in Agra, and she used to buy something called Makhan from a sweet shop nearby. It was one of the most wonderful things I'd ever had - essentially an almost weightless saffron-flavoured foam. We used to have it with pooris, and it was the airiest, most fantastic dessert ever. Its also a dessert of romance; morning dew and moonlight are supposed to play important parts.
I've tried a few times over to find Makhan elsewhere, but only UP and Delhi have even heard of it. I stumbled upon this article in the Hindu that talks about the Delhi version, Daulat Ka Chaat, and a few more references, including blog posts in Cooking with Simi and EOiD (who even had a map of where it is available in Delhi). Lucknow apparently calls it Nimish. Pushpesh Pant, the ever-obliging chronicler of all foods Avadhi, has published a recipe for it. Simple, but tedious, even without the moonlight dew business.
I, however, made an accidental discovery to change all that. One day, I took a family pack of Naturals' Kesar Pista ice cream and left it out to soften a little before being able to dig my spoon in. Of course, I forgot to put it back in the freezer. When I did remember a couple of hours later, I opened the container to see that the entire thing had melted. There was liquid at the bottom and a nice foamy layer of cream floating on top, which looked like (and a a quick taste assured me tasted like) the fabled Makhan!! It was a matter of minutes to skim all that foam off and I had my very own, no-effort version (what is left behind makes very good Kesar Milk or Rasmalai but that's just a bonus). In hindsight its rather obvious. Ice cream is churned to incorporate air into it; that's what makes it creamy. If there's enough fat in the ice cream, the fat floats up to the top along with the millions of air bubbles inside as the ice-cream slowly melts while the liquid settles below.
Of course, its a shade less airy than the real thing but still definitely a foam and still incredibly tasty. And think of how easy it is - buy, forget, serve. I've tried it only with Naturals, but it should work with any ice cream (and any flavour) that has sufficient fat.