For the Graham Cracker Crust: Preheat the oven to 350° Fahrenheit. Line a 9x9 baking dish with parchment paper, letting it hang over both sides.
Add the graham cracker crumbs, melted butter, brown sugar, and salt to a large bowl. Mix to combine, ensuring the crumbs are completely coated with butter.
Press the mixture into the prepared baking dish in an even layer.
Bake 8-10 minutes or until golden brown, and set aside to cool.
For the Ganache: Warm the heavy cream in a microwave-safe bowl for 1-1 ½ minutes or until hot.
Add the chocolate chips, butter, and vanilla. Allow the mixture to sit for 2-3 minutes. Whisk until the ingredients are well combined and a rich chocolate sauce is formed.
Pour the ganache over the cooled crust, and place it back in the fridge to set.
For the Meringue: In a double boiler over medium heat, combine the egg whites and sugar. Be careful not to let the bowl touch the bottom of the pot! Whisk until the sugar dissolves.
Transfer the mixture to the bowl of a stand mixer. Beat 5-6 minutes or until it thickens and becomes glossy.
Add the cornstarch and vanilla, and continue to beat 2-3 minutes or until peaks begin to form.
Spread the meringue evenly over the ganache layer, covering it completely.
Chill the bars in the fridge for at least 4-5 hours or up to overnight.
To toast, place the baking dish under the broiler for 2-3 minutes. Or, run a blow troch over the top. Be careful not to let it burn!
Slice and serve!
Store in an airtight container in the fridge for up to 1 week.