On our first day in Reykjavik, we wondered if we'd stumbled into some modern version of Gulliver's Brobdingnag. Everyone was … so tall. And fit. And wearing technical gear. They looked like they were about to dash up Iceland's volcanos, dive for lobsters in its fjords, or — at the very least — set sail in a high-prowed boat to discover a new continent or pillage an old one. It was a very Viking moment. The secret behind all this outsized vigor (or so we were told) was skyr. This Nordic cousin of Greek yogurt is so well-drained and thick that it's legally classified as a cheese. What distinguishes it from various other cultured milk products is that heated skimmed milk is inoculated with traditional...Read More