Chocolate Pastry Cream

Add the heavy cream and ½ cup milk to a medium saucepan and place over medium heat. Heat the cream while working on the next step.
In a large mixing bowl, whisk together the granulated sugar, dark cocoa powder, cornstarch, egg yolks, and the remaining ½ cup milk until smooth.
Once the cream mixture starts bubbling at the edges of the saucepan, remove the saucepan from the heat. Very slowly drizzle the hot cream into the egg mixture, whisking constantly. Be sure to drizzle slowly and whisk quickly to temper the egg mixture so it does not turn into scrambled eggs.
Once all the hot cream has been added to the egg mixture, pour the custard mixture back into the saucepan and place on the stove over medium-low heat. Whisk constantly until the mixture thickens and is bubbling about 3-5 minutes.
Remove the saucepan from the heat. Add in the semisweet chocolate, salted butter and vanilla extract and whisk until the chocolate and butter are melted and the pastry cream is smooth. If lumpy, pour the pastry cream into a fine mesh strainer over a large bowl. Use the back of a spoon to push through the pastry cream to remove any lumps.
Place a piece of plastic wrap directly on top of the pastry cream to prevent a skin from forming. Chill for at least 6 hours before using.

Store the chocolate pastry cream in an airtight container in the refrigerator for up to 1 week.

Metric conversions are calculated automatically. I cannot guarantee the accuracy of this information.