Soak 2 of the doughnuts in the milk overnight in the fridge.

Sieve the milk and push the doughnut through the sieve (it should be mushy enough).

Add the salt, milk, cocoa powder and sugar (keep a little bit back for later) to a pan and bring to a gentle simmer, whisking in the cocoa powder. DO NOT LET IT BOIL!

Whisk the egg yolks together with the remaining sugar and 

Temper the egg yolks by slowly pouring the hot milk mixture over the them. Pour very slowly and continually whisk.

Add everything back to the pan and slowly heat it. Add the chocolate and stir until it’s melted.

Ensure that it doesn’t boil and that the eggs don’t start to cook. A good way to test if it’s ready is to use a wooden spoon. If the mix coats the back of the spoon without running then it’s good to go. Think of the consistency of custard.

Once you’ve reached custard, add the cream and leave in the fridge to chill for 8 hours minimum, ideally overnight.

Rip up the last doughnut and add it as the ice cream is churning.