Preheat oven to 350°F (177°C). Mix the graham cracker crumbs and melted butter together until completely combined. Press tightly into the bottom and up the sides of a 9-inch pie dish. Bake crust for 8-10 minutes and let cool completely.

It’s best to measure out all of the pudding ingredients before beginning because you will need to move quickly. Whisk the egg yolks together in a bowl. Set aside. Whisk the cold water and gelatin together in a medium saucepan. Allow to sit for 2 minutes to slightly thicken, then turn the stove on to medium-low heat and place the saucepan on top. Whisk in the milk, sugar, and flour. Whisk aggressively to dissolve the sugar, then slowly whisk as the mixture heats.

When the mixture is warm and slowly simmering (not boiling!), slowly drizzle about 1/4 cup (60ml) of it into the beaten egg yolks while whisking it all together. The point of the slow pour and the whisking is to temper the egg yolks. Once the 1/4 cup is added, very slowly pour the egg yolk mixture into the saucepan. Whisk it all together as the mixture begins to thicken. Once bubbles begin to burst at the surface, whisk in the chopped chocolate until combined. Whisk for about 1 more minute as the pudding continues to thicken and bubble. Remove the pudding from heat. If you notice lumps, you can strain the pudding through a fine sieve, but that’s optional.

Pour pudding into the prepared pie crust. Immediately cover the top of the pudding with clear plastic wrap (directly on the surface of the pudding). Allow pudding pie to cool for 1 hour at room temperature before putting into the refrigerator to chill. Refrigerate for 4 hours and up to 24 hours until the pudding has completely set.

Using a hand mixer or a stand mixer fitted with a whisk attachment, beat the heavy cream, confectioners’ sugar, and vanilla on medium-high speed until stiff peaks form, about 5 minutes. Remove plastic wrap from chilled pie and spread or pipe the whipped cream on top. Garnish with optional toppings. Slice and serve.