Set yourself up for success by preparing all ingredients and materials before beginning – you want to have your fine mesh strainer and heatproof bowl ready before your pastry cream thickens, and your chocolate ready to go.

In a medium-sized saucepan, whisk together granulated sugar, cornstarch, and table salt.

Separately, in a medium-sized mixing bowl, whisk together milk, cream, and egg yolks until mixture is uniform (make sure the egg yolks are thoroughly mixed and no longer intact).

Slowly, while whisking the ingredients in the saucepan, drizzle the cream/milk/egg mixture into the saucepan and whisk until evenly incorporated and no lumps remain.

Turn stovetop heat to medium and whisk constantly until mixture begins to thicken to a pudding-like consistency that coats the back of a spoon (your whisk should just be beginning to leave trails through the mixture).

Immediately remove from heat and pour through a fine mesh strainer into a heatproof mixing bowl.

Add chopped chocolate and butter and stir until both are completely melted and well incorporated and mixture is silky smooth and uniform.

Stir in vanilla extract.

Allow pastry cream to cool for about 15-20 minutes longer, stirring occasionally to prevent a skin forming on the surface.

Place a piece of wax paper or parchment paper directly against the surface of the pastry cream (to prevent a skin from forming), cover the dish tightly with plastic wrap, and transfer to refrigerator to chill for 2-4 hours (or up to 3 days) before using.