Pempek, mpek-mpek, or, colloquially, empek-empek, is a savory Indonesian fishcake, made of fish and tapioca, from Palembang, South Sumatra, Indonesia. Pempek is served with a rich sweet and sour sauce called kuah cuka or kuah cuko, or just "cuko". Sometimes local people also eat the dish with yellow noodles and diced cucumber to balance out the vinegar's sourness, or adding chili powder to give the vinegar spiciness.