Nathan Myhrvold describes techniques for cooking the perfect burger, including dousing the patty in liquid nitrogen.

Any food is worthy of trying to achieve the ultimate version of it. Our version of the ultimate burger is a little tough to do at home because it involves liquid nitrogen and a deep fryer. We grind the hamburger, we put it in liquid nitrogen, and then we deep fry it to make a crispy crust after we cooked it sous-vide to make the inside even. 

I think the real trick with making a great burger is to make sure you use a hot enough either flame or pan or barbecue to get the outside really crusty while keeping the inside medium rare. And that's easiest to do if you can cook the burgers very gently first at low temperature to get the inside medium rare, then briefly sear the hell out of it to make the outside crispy.