01 -
Beat cold heavy cream in cold bowl with cold whisk attachment until soft peaks form. Refrigerate until needed.
02 -
Heat water in double boiler over medium heat. Add chocolate, 1/4 cup water, butter, and vanilla. Stir until melted and smooth.
03 -
Whisk egg yolks, 1/4 cup water, and sugar in saucepan over medium-low heat until mixture reaches 160°F, about 10 minutes. Stir constantly.
04 -
Mix egg mixture into melted chocolate until smooth. Cool in ice bath for 5-7 minutes, stirring slowly.
05 -
Gently fold whipped cream into cooled chocolate mixture until smooth. Don't overmix to keep air in mixture.
06 -
Divide into serving cups, cover airtight, and refrigerate at least 4 hours before serving.