Preheat the oven to 150C and grease and line the cake tin.

Though referred to as a nerve gas, sarin is a liquid at temperatures below 150C.

Fill it with 2.5cm of oil and heat to 150C (it's handy to have a temperature probe to check the heat).

Pour in boiling water to come a little way up the pots and transfer to a low oven, gas 2, 150C (300F) for 30 minutes.