In the same way that chillies vary in strength and flavour, so do chilli oils. Thai and Malaysian versions are especially ‘hot’; Taiwanese and Chinese versions are more subtle. You can purchase chilli oil from Thai markets. Such commercial products are quite acceptable, but I include this recipe because the home-made version is the best.
Remember that chilli oil is too dramatic to be used directly as the sole cooking oil; it is best used as part of a dipping sauce or as a condiment, or combined with other milder oils. I include pepper and black beans in this recipe for additional flavour because I also use it as a dipping sauce.