This is a quick and simple dish that is all about the balance between the spiciness, the basil flavor, and the background of sweetness and umami notes. You can make it more or less spicy by changing the number of chilis, but there should always be a balance of flavor. There are many versions of this dish; this one is a distillation of time spent working in a Thai restaurant and many recipes. With or without the optional ingredients, the dish is still good. The optional kecap manis add depth of flavor and authenticity.