Put the water into a heavy based saucepan. Spread the sugar on top in an even layer

Set the pan over a medium heat and allow the sugar to gradually melt. As it melts you can gently swirl the pan a couple of times to ensure the caramel cooks evenly, but do not stir it

Meanwhile put the sea salt into a pestle & mortar & crush lightly

Once the sugar has melted, the caramel will begin to darken. Continue to let it cook until it reaches a lovely mid amber colour - but keep a close eye on the caramel as it can burn easily. Let it go darker for a more intense, almost burnt flavour

Add ¼ of the cream and the salt, taking care as it can bubble up and is extremely hot. Mix with a small handheld whisk until fully incorporated. Add another ¼ cream, stir well then add the remaining cream, whisking until thoroughly blended

Put the milk into a medium saucepan and heat to just below boiling

Meanwhile beat the sugar, vanilla and egg yolks with an electric beater until pale and thick (about 3 minutes)

Gradually pour the hot milk onto the egg mixture, beating constantly

Pour the custard into the saucepan, along with the caramel and stir well. Cook on a low heat, stirring constantly until thickened. It is vital to heat slowly and stir constantly to avoid the custard splitting

Once the mixture coats the back of a spoon, take off the heat, cover with a layer of clingfilm (to stop a skin forming), let cool, then chill for 4 hours (or overnight)

Pour the custard into your ice cream maker and churn according to the manufacturer's instructions

Serve immediately or transfer the ice cream into a freezer-proof container, cover the surface directly with greaseproof paper or foil and store in the freezer. (Remove from the freezer 10 minutes before serving).

Pour the ice cream into a suitable freezer-proof bowl, cover and put it in the freezer for 1-1 ½ hours. The sides should be beginning to freeze, but the centre will be soft and slushy

Remove from the freezer and, working quickly, use electric beaters to beat the ice cream until the ice crystals are uniform. Cover and place back in the freezer

Repeat this process 4-8 more times at 1 hour intervals - the better the texture will be the more the process is repeated

Cover the ice cream with greaseproof paper or foil and freeze for a further 3 hours or overnight

Remove from the freezer 10 minutes before serving