Place the milk, sugar, eggs and 100 g of the butter in a saucepan and heat to boiling point.

Place into the bowl of a mixing machine with a spade attachment and mix on low speed until the mixture is cold.

Add the remainder of the butter, in two stages, increasing the speed as the mixture becomes creamy and light, flavour and colour as desired, e.g. chocolate with the addition of 150 g melted couverture; coffee with the addition of coffee extract.