Boil the milk and stir into it the cornflour smoothed with a little of the milk; whip up the eggs, and carefully stir in the milk (which should have been allowed to go off the boil) without curdling it; add sugar and vanilla to taste, and stir the custard over the fire until it thickens, placing it in a jug into a saucepan of boiling water. Arrange the macaroons in a glass dish, and when the custard is cool enough not to crack the dish, pour it over them and sprinkle some ground almonds on the top. Serve cold.
Dr. Allinson's Cookery Book (1915).