The natillas (custard) recipe is one of the most widely known through Spanish confectioneries. We are talking about a cream made from milk, sugar, egg yolks, and lemon or vanilla flavoring.
Although we are not certain of its true origin, it is believed to be created in convents. Its simple recipe, natural properties (coming from the eggs and milk), and its low cost make it a good recipe for the convents, a place where the making of sweets has always been fostered amid an austere culture.