Lamb khorma is sensuous curry made by simmering lamb with yogurt and cream and thickening the sauce with a cashew paste. If you can find goat's milk yogurt or sheep's milk yogurt, it will make a discernable difference in this dish.
Ghee
Ghee, a type of cooking butter used in Indian cooking, can be purchased in jars at Asian or Indian markets, but it is easy to make yourself.
Cube 1 pound of cold unsalted butter, place in a sauce pan, and set over low heat. Once the butter has melted, increase the heat slightly. The pure butterfat will become very clear. Some foam will rise to the top; skim it away.
Increase the heat slightly and continue to cook the butter until the milk solids that have fallen to the bottom of the pan turn a deep golden color.
Immediately remove the pan from the heat. Ladle the clear butter-fat, or ghee, into a clean container; discard the liquid at the bottom of the pan. You can keep ghee in the refrigerator for up to 2 weeks.
Pan Roasting Nuts
You can buy roasted peanuts and cashews to garnish some of our South-east Asian stews like this curry. For the best flavor and texture, however, consider toasting your own. You can use the same technique to pan-roast spices and seeds for a depth of flavor you simply can't find in store-bought spice blends.
Let a heavy-bottomed skillet or sauté pan get very hot over high heat. Add the nuts, spices, or seeds to the pan in an even layer. Swirl the pan gently to keep the ingredients in motion constantly. The aromas will open up and deepen dramatically.
Once the nuts, spices, or seeds begin tot give off a noticeable aroma, keep a close eye on them. They can go from perfect to overdone in a few seconds. Pour them out of the pan into a bowl just before they are the shade of brown you want.
