This is an unbelievable dessert, a real indulgence. Store in a plastic container or an old ice cream tub in your freezer and this ice cream can last up to a month.
To make the ice cream mixture, whisk the egg yolks in a mixing bowl, add the milk and transfer to a pan on medium heat for 5 minutes. Strain the mixture. Then stir in the heavy cream and refrigerate overnight.
To make the caramel mixture, heat the sugar in a pan over medium high heat, use a fork to stir. Stop stirring and add the single cream. Pour into a bowl and add the sea salt. Chill the caramel. Once chilled for about 30 minutes, pour the caramel mixture into the ice cream mixture. Add the vanilla extract, stir and refrigerate until hardened but not too much. It should be very easy to scoop out.