Spray a 9-inch pie pan with cooking spray. Combine the crust ingredients and press firmly into the prepared pie pan. Refrigerate while preparing the filling.

Prepare the ganache by combining the cream, butter, and vanilla in a saucepan. Bring to a simmer over medium heat. Remove from heat, add the chocolate chips, and let sit for 5 minutes. Stir until the mixture is smooth and glossy. Spread half of the ganache in the pie pan over the crust. Put crust back in refrigerator. Let the rest of the ganache cool.

Prepare the filling by combining the milk, cream, sugar, cornstarch, egg yolks, vanilla, and salt in a heavy saucepan. Place over medium heat and cook, whisking, until the mixture starts to bubble and has thickened.

Strain the mixture into a mixing bowl and stir in the remaining ganache. Place a piece of plastic wrap directly on the surface of the filling and refrigerate for 1 hour.

Combine the topping ingredients and beat until stiff peaks form. Do not over-beat.

Spread the filling into the pie pan over the cooled ganache. Smooth the top with a spatula, then spoon on the whipped chocolate cream. Garnish with some cocoa powder or shaved chocolate, if desired.

Can be eaten immediately or stored in the refrigerator until serving time. Can be made a day ahead.