Serawa langut is ‘the bread of disappointment’ (serawa is a sweet dish made of plantains, sweet potatoes or bread-fruit; langut, to watch expectantly). A Malay who has been to a house where he expected to be entertained, and has had to come away hungry will say that he has eaten ‘serawa langut‘.
Maxwell, W. Notes and Queries 3. In W. Maxwell, Notes and Queries of the Malaysian Branch Royal Asiatic Society (reprint 15). Kuala Lumpur: Malaysian Branch Royal of the Royal Asiatic Society; 1997. p61-62.