Finely chop the 70 g of dark chocolate and set aside.

If you prefer your drink hot for longer, warm your serving cups with hot water.

If using cornstarch, mix 1/2 tsp with about 1 tbsp of cold milk to make a smooth slurry.

In a small saucepan, combine 300 ml of whole milk, 40 ml of heavy cream, 1 tbsp of Dutch process cocoa powder, 1 tbsp of sugar, and a pinch of sea salt. Whisk these ingredients together.

Heat the milk mixture over medium-low heat, whisking often until steaming with small bubbles around the edges. Do not let it boil.

If using cornstarch, add the slurry and keep stirring. Allow it to simmer gently for 1 to 2 minutes until slightly thickened.

Remove the pan from heat. Immediately add the chopped chocolate and 1/4 tsp of vanilla extract. Stir until melted and smooth.

Taste and adjust sweetness if necessary. If too thick, thin with warm milk; if too thin, let simmer longer or add more chopped chocolate.

For the silkiest texture, strain through a fine mesh sieve into a jug.

Pour the chocolate into warmed cups and serve immediately. Optionally top with whipped cream or a dusting of cocoa.