Bumbu kacang is an Indonesian peanut sauce made from ground roasted peanuts blended with garlic, shallots, chilies, palm or brown sugar, and often coconut milk and lime juice, giving it a sweet, savory, spicy, and tangy flavor. It's a foundational condiment in Indonesian and Malay cooking, used as a dipping sauce for satay, a dressing for gado-gado (vegetable salad), and a flavoring base for soto (soup) and lontong (rice cakes). Its consistency ranges from a thick paste to a thinner, pourable dressing depending on how much it's diluted with water or coconut milk, and regional versions may add shrimp paste or roasted coconut.