Melt 125 grams of sugar in a small heavy-bottomed saucepan over medium heat.

Once the sugar has melted, add the butter and mix well. The caramel will foam up and it takes 1-2 minutes to combine.

Now add the cream a little at a time. The caramel will foam up again each time cream is added. Once the caramel and cream are mixed together, add the sea salt and stir it into the mixture.

Add the remaining 125 grams of sugar and stir it into the caramel, bringing it back to a boil over medium heat.

Heat the caramel up to 130 degrees Celsius (266 degrees Fahrenheit) (use a sugar thermometer to check the temperature).

If you don't have a sugar thermometer, you can check the consistency of the caramel: when you can separate the caramel in the saucepan with a spoon and it slowly comes back together, it’s ready.

It requires some patience, it can easily take 30 minutes.