"Pastéis de nata were created before the 18th century by Catholic monks at the Jerónimos Monastery (Portuguese: Mosteiro dos Jerónimos) in the civil parish of Santa Maria de Belém, in Lisbon. These monks were originally based in France where these pastries could be found in local bakeries. At the time, convents and monasteries used large quantities of egg-whites for starching clothes, such as nuns' habits. It was quite common for monasteries and convents to use the leftover egg yolks to make cakes and pastries, resulting in the proliferation of sweet pastry recipes throughout the country.
Following the extinction of the religious orders and in the face of the impending closure of many of the convents and monasteries in the aftermath of the Liberal Revolution of 1820, the monks started selling pastéis de nata at a nearby sugar refinery to bring in some revenue. In 1834, the monastery was closed and the recipe was sold to the sugar refinery, whose owners in 1837 opened the Fábrica de Pastéis de Belém. The descendants own the business to this day.
The Pastéis de Belém were mentioned by The Guardian as the 15th most tasty delicacy in the world."