This is my take on Modernist cryo-fried burgers as described in Modernist Cuisine
. They are a perfect medium rare throughout the inside with a thin, crispy outer crust. This is achieved by cryo-frying the burgers: cooking them sous vide, briefly freezing them in liquid nitrogen to keep the inside from overcooking, and then frying them in hot oil.
The burgers were juicy and tender with an extremely satisfying crunch through the browned surface. The actual work making the burgers was minimal, but the setup complicated. I cooked these as part of Fried Day at the Instructables lab when we already had both liquid nitrogen and pots of hot oil ready to go.
Here are the abbreviated instructions; go through each step for pictures and more information:
Mix ground beef with salt to achieve a 0.8% salt concentration, refrigerate for an hour
Cook beef sous vide to an internal temperature of 131°F
Freeze the outside of the burgers in liquid nitrogen for 30 seconds
Fry the burgers in oil at approximately 425°F for 30 seconds
Many thanks to ReneediCherri