What it is: Regular butter contains milk fat, milk solids, and water. Ghee is just the milk fat (clarified butter), with the water and milk solids removed. Clarified butter is made in the French tradition, too, but the crucial difference is that ghee is simmered for a while, to brown the milk solids before they are strained out, which leaves behind a wonderful toasty caramelized flavor. French clarified butter doesn’t get a prolonged simmer so it tastes more neutral.
To make it: In her seminal book, Classic Indian Cooking, Julie Sahni makes ghee like this: First, melt about a pound of butter over low heat. Once the butter is melted, increase the heat to medium. The butter will foam as the moisture evaporates. You don’t need to stir at this point. The foam will subside after about 10 minutes, when all the water has evaporated. Soon after, a second foam will form on top of the ghee: Now it’s almost done and should be watched closely. You’ll see the milk solids have separated from the golden fat, and many of them have sunk to the bottom—watch the milk solids carefully, and stir to make sure they don’t burn. The ghee is done when the milk solids are a nice golden brown and smell toasted. Let the ghee cool slightly before straining it through cheesecloth to remove the milk solids. The resulting ghee can be kept in an airtight container for one month or in the fridge for four months.
Where it comes from: Ghee is very important in Indian cuisine. It is used not only in cooking, but also in Hindu rituals and Ayurvedic medicine. In his book, On Food and Cooking, Harold McGee says that ghee was probably born of necessity: Butter spoils quickly in the heat, while ghee keeps for a long time and is shelf-stable.
How to use it: Because ghee is pure fat, it has a much higher smoke point than butter (milk solids burn at a relatively low temperature). That means you can use it for high-heat sautéing or frying, much as you would canola or peanut oil. You can certainly use it in any Indian recipe, but its nutty flavor works well in many contexts. It makes simple sautéed vegetables incredibly delicious.