• Preheat the oven to 350°F. Spray a 9-inch pie plate with cooking spray.

Make the crust:

• In the bowl of a food processor, pulse the graham crackers and salt until finely ground. Pour in the butter and pulse until evenly moistened. Press the crumb mixture into the bottom of the pie plate and about 1 inch up the sides. Bake for 10 minutes, then set aside to cool.

Make the filling:

• Place the gelatin in a small bowl, add the boiling water, and stir until dissolved. Set aside.
• In a medium saucepan, mix the granulated sugar, cocoa, cornstarch, and salt. Gradually add half the milk, whisking until smooth. Whisk in the rest of the milk. Turn the heat on to medium and cook, whisking constantly, until the mixture thickens and comes to a boil, about 10 minutes.
• Remove from the heat. Add the chocolate and stir until melted. Stir in the vanilla and reserved gelatin. Pour the mixture into the pie crust and place in the refrigerator to set, at least 4 hours.

Make the whipped cream:

• Beat the cream and sugar in a medium-sized, deep bowl until soft peaks form. Spread over pie or pipe on using a piping bag fitted with a star tip. Garnish with cocoa or chocolate shavings.
• The pie can be covered and stored in the fridge for up to 2 days.