Add <quantity>375<unit>g</unit></quantity> of whole milk and <quantity>375<unit>g</unit></quantity> of double cream to a pan

Place over low heat until it reaches <temperature>80<unit>°C</unit></temperature>

Add <quantity>9</quantity> egg yolks and <quantity>300<unit>g</unit></quantity> of caster sugar to a bowl. Reserve the egg whites for other preparations

Whisk until the mixture is pale yellow and creamy

Carefully pour the hot milk mixture into the egg yolk cream, in 3 batches, while constantly whisking

Transfer the mixture back to the pan

Cook over low heat, stirring constantly until it reaches <temperature>78<unit>°C</unit></temperature>

Transfer to a heat proof container and refrigerate until completely cooled down. The ice cream base custard is ready