This is an excerpt from A Treatise of Portuguese Cuisine from the 15th Century
(Portugal, 15th c. - Fernanda Gomes, trans.)
The original source can be found at
Lochac Cooks' Guild Website
34 - Tigelada de leite. Batam muito bem quatro ovos com cinco colheres de açúcar, cinco de farinha de trigo, e uma pitada de sal. Em seguida untem umas forminhas de barro com bastante manteiga, e coloquem nelas o creme, levando ao forno para assar, com um pouquinho de manteiga por cima.
Milk custards. Beat 4 eggs very well with 5 spoons of sugar, 5 of wheat flour, and a pinch of salt. Next grease some little clay rammekins with lots of butter, and place the cream inside, putting them in the oven to cook with a little butter on top.