A sweetheart cake or wife cake or marriage pie is a traditional cantonese cake with a thin crust of flaky pastry, and made with a filling of winter melon, almond paste, and sesame, and spiced with five spice powder. "wife cake" is the translation of lou po beng from cantonese, and although the meaning is "wife", the literal translation is "old lady cake", paralleling the colloquial usage of "old lady" for "wife" in american english. in hong kong, it is known as a specialty of yuen long.

Source: Wikipedia