A sambal is a fresh or cooked relish. Sambal oelek is a spicy relish which is often used in conjunction with other sambal ingredients. It is made from ground chilies, salt and vinegar or tamarind. Tamarind is a very acidic fruit which gives sambals a particularly sharp taste. In a traditional oelek, the chilies are not seeded, adding more heat.
Slice 250 g (8 oz) button mushrooms. Slice 2 spring onions (scallions) and 4 medium celery stalks as in the main recipe. Trim 150 g (5 oz) mung bean sprouts. Finely chop 1 clove garlic. * In a wok, heat 2 tablespoons oil over medium heat. Cook mushrooms, spring onions and celery, stirring, 2 minutes. Add sprouts and garlic. Toss over high heat, 1 minute. Add 2 tablespoons each of rice vinegar and soy sauce. Remove from heat. Season with salt to taste. Serve warm.