Combine the sugar and egg yolks and beat until thick and pale yellow.
Bring the milk to a low simmer in a pan.
Beat the milk into the egg/sugar mixture in a slow stream.
Pour the mixture back into the pan and place over low heat. Stir continuously until the custard thickens slightly (around 65-70°C) and just coats the back of a spoon. Don't over-heat, though, because at around 76°C you will scramble the eggs! Immediately remove from the heat.
Transfer the mix to a (chilled) jug and cool the mix to 5°C in freezer.
Stir in the cream.
Freeze using an ice cream machine until the consistency of soft (whippy) ice cream.
Transfer into freezing dish and put back into freezer and freeze until core is -18°C.