• Separate the egg whites into a large, clean glass bowl or bowl of a stand mixer and set aside to come to room temperature. Make sure there's no trace of yolk in the bowl or you won't be able to whip the egg whites to stiff peaks. In a separate bowl, sift 1 cup of granulated sugar through a sieve to get rid of any clumps or specks of debris and set aside.
• Lightly spray a 9" deep-dish pie pan or a 9" tart pan with non-stick cooking spray and preheat your oven to 325°F.

Make the Graham Cracker Crust:

• In a large bowl or a food processor, mix the graham cracker crumbs and granulated sugar until combined. Add the melted butter and mix until evenly coated.
• Pour the crumb mixture into the pie dish and spread it out evenly. Use the flat side of a clean glass or a measuring cup to press the crust tightly and evenly into the bottom and around the sides of the pan.
• Bake the crust in the preheated oven for 10 minutes. Remove from the oven and turn the oven off.

Make the Chocolate Ganache:

• Add the chocolate to a large glass bowl and set aside.
• Add the ¼ cup salted butter and 1 cup heavy cream to a pot and heat until the butter is melted and the cream is simmering gently. Pour the liquid into the bowl of chocolate and stir until the chocolate is melted and smooth.
• Pour the chocolate ganache into the graham cracker crust. Place the pie in the fridge or freezer so the ganache is set when you add the meringue.

Make the Meringue Topping:

• Add the cream of tartar to the bowl of room temperature eggs. In a clean pot, add ½ cup sugar and ¼ cup water. Place the pot over medium-low heat and begin heating the sugar syrup to 240°F.
• Use a hand-held mixer or a whisk attachment in the stand mixer and beat the egg whites to soft peaks. They'll be foamy at first and then start to thicken after about 1 minute. Gradually add the remaining ½ cup sifted granulated sugar and continue to beat the meringue to medium-stiff peaks.
• Use a digital instant-read thermometer or a candy thermometer to check the temperature of the sugar syrup. Once it reaches 240°F, take the syrup off of the heat and, with the mixer running, slowly drizzle the syrup into the bowl with the meringue. Once all of the sugar syrup has been added, finish whipping the meringue until it reaches stiff peaks. You should be able to turn the bowl upside down without the meringue moving at all.

Assemble and Toast the Meringue:

• Take the pie out of the fridge or freezer and spread the meringue evenly over the top. Use a spoon or spatula to create some peaks or a swirl in the meringue, then lightly brown the top with a kitchen torch, a torch lighter, or by placing the pie directly under your oven's broiler for about 3 minutes. If using the broiler, make sure you keep an eye on it so the meringue browns evenly and doesn't burn.
• Keep the pie in the fridge or freezer until the ganache is fully set and you're ready to slice and serve. Keep any leftovers, covered, in the fridge for up to 3 days. You can also freeze the pie for 3-4 months.