Chocolate custard ice cream with eight egg yolks

Put the cocoa powder into the large saucier first, then the sugar, keeping the airborne powder down.

Work the egg yolks in to bind the cocoa powder to something viscous and fatty before any liquid goes in, which prevents clumps that would have to be strained out later.

Whisk in the half and half, the cream and the vanilla very thoroughly before adding heat.

Whisk almost non-stop over medium heat to between 170 and 175F, where it becomes a custard thick enough to coat the back of a spoon; no tempering of the yolks is needed because the flavourings are cocoa powder and extract rather than a steeped flavour.

Kill the heat and check the nappe: coat the back of a spoon, drag a finger through, and the line should sit rather than run.

Cool it down over an ice bath so it stops cooking.

Age the mixture overnight in the refrigerator so the egg and dairy emulsion smooths out; it churns faster and much smoother on the palate.

Start the machine before the mixture goes in, and get it in as quickly as possible.

Churn longer than the vanilla because of the fat, about 20 minutes, ignoring any timer or beeper and going until the motor is heard struggling against the mixture.

Pack into pint containers with an ice cream spade and a stiff plastic spatula together.

Harden in the freezer a couple of hours.