Chocolate Pots de Crème

Place the finely chopped chocolate in a heatproof bowl set over a pot of barely simmering water — the bowl should not touch the water. Stir occasionally until the chocolate is fully melted and perfectly smooth. Alternatively, melt in a microwave in 30-second bursts at 50% power, stirring between each. Remove from heat as soon as the last lumps dissolve — residual heat finishes the job. The melted chocolate should be smooth, glossy, and between 45°C and 50°C.

Combine the heavy cream, whole milk, espresso, and vanilla in a saucepan. Heat over medium heat, stirring occasionally, until wisps of steam rise and small bubbles form around the very edge of the pan — just below a simmer, around 80°C to 85°C. Do not boil: a boil will scald the milk, encourage curdling when added to the yolks, and dissipate the delicate aromatic compounds of the vanilla. Remove from heat the moment a ring of bubbles appears at the pan's edge.

Whisk the egg yolks and caster sugar in a large bowl until just combined and slightly pale — about 30 seconds of active whisking. Do not whip air into the yolk mixture: the goal is a smooth, uniform liquid that will blend easily with the hot cream, not a foam that will bake to a spongy custard. The sugar should be fully dissolved and no streaks of undissolved sugar should remain. The mixture will be a rich golden-yellow, slightly viscous, and smooth.

Pour the hot infused cream into the yolk mixture in a very thin, slow stream, whisking constantly and gently — the stream should be no wider than a pencil. This gradual warming prevents the yolks from scrambling. When all the cream is incorporated, pour this mixture over the melted chocolate and stir slowly from the centre outward until the custard base is completely smooth and glossy. Add the fleur de sel and stir once. Strain through a fine-mesh sieve into a pouring jug to remove any cooked egg threads and the espresso grounds. Skim any surface bubbles with a spoon — a bubbly surface bakes to a pocked, matte finish.

Preheat the oven to 150°C (300°F). Arrange small ramekins or oven-safe pots in a deep roasting tin. Pour the custard through the fine sieve once more into the ramekins, filling each to just below the rim. Slide the tin into the oven and pour very hot water into the tin to come halfway up the sides of the ramekins. Cover the entire tin loosely with foil and bake for 30 to 40 minutes until the custards have set at the edges with a distinct wobble at the centre when the tin is nudged — like a slow, gentle jelly. Remove from the bain-marie, cool to room temperature, then refrigerate uncovered for at least 3 hours before serving. Serve in the pot, directly at the table.