Chocolate Creme Patissiere Pastry Cream

Pour the milk and vanilla into a large heavy-bottomed saucepan over medium-high heat and bring to a boil. 

While the milk and vanilla are being heated, add the sugar, eggs, egg yolks, cornstarch, cocoa powder, and salt into a bowl.

Whisk until you have a thick, smooth mixture. Set aside until the milk and vanilla come to a boil.

Once the mixture starts to boil, remove it from the heat. Slowly pour about 1/2 of the hot milk in a thin stream into the egg mix, while whisking constantly to temper the egg mixture. When the eggs have been tempered add the egg mix back into the hot milk in the saucepan. Heat the custard over medium heat while whisking vigorously until it starts to thicken about 3-5 minutes depending on the heat level.

Let the custard come to a gentle boil and release some bubbles, as soon as this happens remove from the heat and add the bittersweet chocolate chips. Whisk until completely melted. If you need to slide the saucepan back over low heat to finish melting you can do so. 

Once the chocolate is melted, add the butter and whisk until it's completely melted into the custard.

Immediately pour the pastry cream into a bowl and cover the surface with plastic wrap to prevent a skin from forming on the top. Allow it to cool off and come to room temperature and then chill in the fridge at least 4 hours or overnight. After chilled (stir if needed) and use liberally!