How to Make It
In a medium stainless-steel bowl, combine the egg yolks with 1/4 cup of the sugar and the Cognac. Set the bowl over a medium saucepan of simmering water. Using a handheld electric mixer, whisk the mixture constantly at medium speed until pale yellow and thick, about 4 minutes. Remove the bowl from the pan once in a while, whisking all the time, so the mixture doesn't get too hot.
Remove the bowl from the saucepan, still whisking, and add the chopped chocolate, butter and salt. Set the bowl over the water and stir, using a wooden spoon or a heatproof spatula, over low heat until the butter and chocolate are melted. Remove the bowl from the heat and let the chocolate mixture cool to room temperature, stirring often. Refrigerate until slightly chilled, about 20 minutes.
In a medium stainless-steel bowl, whip the cream with the remaining 1 teaspoon of sugar until the cream holds soft peaks. Using a rubber spatula, blend one-third of the cream into the chocolate mixture to lighten it, then carefully fold in the remaining cream until blended. Cover and refrigerate the mousse until firm, at least 2 hours.
Spoon 1/3 cup of the mousse onto each plate. Set 2 apricot halves next to the mousse and shave some chocolate over each servings.
If Valrhona is not available, choose another brand that contains a minimum of 50 percent cocoa, such as Lindt's extra-bitter chocolate. The additional cocoa makes desserts taste as chocolatey as they look.