Place the water in a small bowl and sprinkle gelatin over the surface. Let it stand for 5 minutes to soften.

In a medium saucepan, combine the cream, coffee beans and sugar. Heat over medium-low heat until the mixture is scalding (just prior to a simmer). Remove from heat. Add the chocolate and set aside for one minute, then stir until chocolate melts and the mixture is smooth.

Place the bowl of softened gelatin in a small saucepan. Add enough boiling water to the saucepan to come three-quarters of the way up the side of the bowl. Use a fork to whisk the mixture until the gelatin dissolves. Alternatively, microwave the softened gelatin for 10-15 seconds (don’t let it boil) and stir to dissolve fully – rub a little between your fingers to ensure there are no grains.

Add the softened gelatin into the cream mixture and whisk to incorporate fully.

Strain the mixture into a large jug or bowl and whisk in the sour cream until smooth.

Pour into twelve 2-ounce demitasse cups or other small dishes, or six larger dishes (such as the martini glasses I used). Allow to cool to room temperature, then cover with plastic wrap and put into the refrigerator till chill until firm (at least 2 hours, but can be overnight).

Put 3/4 cup granulated sugar and water in a high-sided medium saucepan. Over a low heat, stir the sugar and water until the sugar dissolves. Then stop stirring and turn up heat to high until the sugar comes to boiling. The bubbles will be fast and furious for a while, then will calm down and the bubbles will get fat and lazy. If any sugar crystals form on the side of the pan, brush them down with a bit of water using a pastry brush. Keep an eye on the mixture; it will turn colour initially to light amber, then a medium amber. Keep going until it starts turning a darker copper colour – there is a perfect moment for getting a dark, smoky caramel when it briefly sends up smoke, but before it burns!

Immediately remove the pan from the heat and very carefully add 1/2 cup heavy cream, stirring gently but carefully with a wire whisk. The mixture will bubble up briefly, so be careful of splatters. Keep stirring – if the mixture seizes up, don’t worry; return to the heat briefly and it will become smooth again.

Let the caramel cool before stirring in 1/4 teaspoon fleur de sel or sea salt.

About 20-30 minutes before serving, take the panna cottas out of the fridge and spoon a few teaspoons of the caramel over top of each (you may need to gently reheat the caramel in the microwave to make it workable). Gently spread the caramel across the surface using the back of a teaspoon till it evenly covers the panna cotta. Sprinkle a few extra grains of fleur de sel or sea salt over top and a dollop of cream or creme fraiche.