Sous-vide is a special way to cook food in a bag that sits in hot water. Imagine you have a lunch bag and you put a sandwich in it. Now imagine you fill a big pot with hot water and put your lunch bag in the pot. You leave the bag in the hot water for a long time, and when you take it out, your sandwich is perfectly cooked all the way through, and very juicy too! This is basically what sous-vide is. Chefs like to use this cooking method because it is very consistent and makes food taste great. They think of it like magic!