|bittersweet chocolate, 60% to 62% cacao, chopped||.|
|pure vanilla extract||.||.|
|cream of tartar||.||.|
Have ready a fine-mesh strainer suspended over a stand mixer bowl and a handheld mixer.
In the top of a double boiler set over hot, not simmering, water (do not let the bottom of the container touch the water), heat the chocolate and cream. Stir often with a silicone spatula until the chocolate is completely melted. Remove it from the heat.
In a medium bowl, lightly whisk the egg yolks. Stir several tablespoons of the hot chocolate mixture into the yolk mixture. Gradually pour the yolk mixture into the remaining chocolate mixture, stirring constantly.
Continue stirring, occasionally scraping the bottom of the container to ensure uniform consistency. Heat the mixture to just before the boiling point (170° to 180°F/77° to 82°C). Steam will begin to appear and the mixture will be slightly thicker than cream. It will leave a well-defined track when a finger is run across the spatula. Immediately remove the container from the heat and pour the mixture through the strainer into the mixer bowl, scraping up the thickened cream that settles on the bottom of the container. Press it through the strainer and stir in the vanilla.
Press a piece of plastic wrap onto the surface of the chocolate custard to prevent a skin from forming. Refrigerate for 2½ to 3 hours, stirring every 20 minutes, until cool to the touch. If you are ready to fill the cake-lined pan sooner, you can speed cooling by setting the bowl in an ice water bath and stirring frequently. Do not let the mixture get too cold or it will be too stiff to incorporate air from the meringue. The ideal temperature is 65° to 68°F/19° to 20°C.
Copyright © 2014 by Cordon Rose, LLC. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.