This is the best-known, best-loved sauce for satay. It is also used for Gado-Gado, and goes well with any grilled meat or hamburger steak.
If you like your satay sauce chilli-hot, there are several quite passable powdered instant sauces on the market. For making it yourself, there are various so-called short cuts, most of them involving crunchy peanut butter. Avoid these; the method described below is as easy, cheaper, and much nicer.