Start by measuring out your ingredients and cutting the butter into medium blocks.
Then in a medium heavy bottomed saucepan, pour in the sugar and water and give it a good mix. Before placing on the stove on a medium heat, it should start to bubble and when it does you can swirl the pan around gently every 20 seconds or so. But DON'T STIR as this might crystallise the sugar. Be patient and keep an eye on it to make sure it does not burn.
Once the caramel has reached an amber color, take it off the heat and VERY CAREFULLY pour in the room temp double cream (heavy cream), it should bubble violently. Whisk well. (but carefully)
Next, add in the cubes of butter and whisk well until you have a glossy caramel sauce.
Finally, add in the vanilla and sea salt and give it another good stir with a rubber spatula. Pour into a small bowl or cup and allow to cool completely before enjoying!
And that's it! You'll be left with a gorgeous silky smooth caramel, that can be used warm as a sauce. Or, as a soft set caramel at room temp, hell this is even delish straight from the fridge!