Step 2

Have ready a fine-mesh strainer suspended over a medium bowl. Set aside. In a small saucepan, whisk together the sugar, cocoa and salt. Whisk in the milk until smooth, then whisk in the cream.

Step 3

Heat the mixture on low heat, stirring constantly with the whisk, until it begins to boil. Cook at a low boil for 1 minute, continuing to stir, until thickened.

Step 4

Remove the pan from the heat and whisk in the egg yolk and vanilla. Scrape the chocolate custard into the strainer. Press it through the strainer and scrape any mixture clinging to the underside of the strainer into the bowl.

Step 5

Divide the chocolate custard into two ramekins or 6-ounce cups. Cover tightly and freeze for at least 30 minutes, and up to 45 minutes, before serving. It is at its best texture at this point, when only partially frozen. If you are making it ahead of time, refrigerate until 30 minutes before serving time, and then freeze it for 20 to 30 minutes. Note: The recipe can be doubled to serve four.