Most of the recipes involving Indian food start with making tadka or tempering. Every time I wrote recipes involving tadka I thought of writing a post on how to make tempering.
Generally the base for tempering is oil, but sometimes ghee (clarified butter) is also used. There are different ways tempering can be made. Some use mustard seeds, some use cumin seeds, some use both. This is how a simple tempering is made - Heat some oil. Once the oil is hot enough, add mustard seeds, asafoetida and turmeric powder.
Other ingredients or spices such as curry leaves, green chillies, red chillies, ginger, garlic are added while making the tempering depending on the recipe.