In a bowl, combine the graham cracker crumbs, butter, sugar, and salt to make the crust. The bottom and sides of a 9-inch pie plate should be pressed. Refrigerate for around 30 minutes, or until firm. turn the oven on to 350 degrees. About 12 minutes into baking, the crust should be firm and starting to become golden. Allow to fully cool on a wire rack.

Creating the filling In a medium saucepan, sift together the sugar, cocoa powder, cornstarch, and salt. Whisk milk in gradually. Cook while stirring continuously until nearly boiling over medium-high heat. Add chocolate to the medium-low heat setting. Cook for about 2 minutes, stirring regularly, until chocolate has melted and the sauce is thick. With the heat off, whisk in the vanilla and butter until smooth. Cover crust with chocolate mixture.

Creating the topping Make an ice bath and set it away. 2 teaspoons of cold water in a small bowl with gelatin on top. Allow to stand for three minutes or until soft. In a medium saucepan, combine the cornstarch, salt, and 1/4 cup sugar. Whisk in the milk gradually. Stirring continually, cook for about 5 minutes over medium-high heat, until the mixture is thick and boiling. With the heat off, whisk in the gelatin mixture and allow it to cool fully. Rum and vanilla are combined. If necessary, briefly submerge pan in ice water to thicken. Don't let it entirely dry out. Place aside.

Egg whites should be placed in the whisk attachment-equipped bowl of an electric mixer.Beat at a moderately slow pace until gentle peaks appear. Slow down the pace and keep beating while making syrup.

Stirring to ensure that the sugar is dissolved, bring the remaining 1/2 cup sugar and 3 tablespoons water to a boil in a saucepan. To stop crystals from forming, use a wet pastry brush to wipe over the pan's sides. Cook without stirring until a candy thermometer reads 240 degrees for the syrup.

Increase the mixer's speed to high and beat the egg whites just long enough for firm peaks to develop. Pour syrup into egg whites right away in a slow, steady stream close to the side of the bowl, avoiding the whisk. For roughly 7 minutes, beat until glossy and cooled.

In three batches, gently fold the meringue mixture into the reserved gelatin mixture. Into the chocolate-filled crust, mound the mixture. Pie should be chilled for up to overnight before serving.