Gently warm the milk and cream in a saucepan without letting it boil; it should be 85°C when tested with a thermometer.
Meanwhile, whisk the egg yolks and sugar in a large mixing bowl to a thick white paste. Gradually pour the cream mixture over the egg yolks in a steady stream, whisking continuously. Pour the mixture back into the pan and heat to 78°C – again a thermometer is essential here. Don’t stop mixing until the custard is cooked.
Pass the custard through a fine sieve and allow to cool. This base can be used with most flavours, and is used in most of the ice creams in this section.