1 Prepare the oven and pan: Preheat the oven to 350℉. Line a 9×13-inch ungreased glass baking dish with parchment paper, leaving enough of the paper hanging over the sides to use as a sling to remove the bars once they’re baked.
2 Make the crust: Add the graham crackers to the bowl of a food processor and pulverize them until they are finely ground and resemble sand. You should have a little over 3 cups once ground. (If you don’t have a food processor you can also do this by placing the graham crackers in a ziptop bag and smashing them with a rolling pin.)
Add the melted butter, light brown sugar, and salt; pulse until fully combined.
3 Transfer to the prepared baking dish: Spread the graham cracker mixture evenly in the prepared baking dish. Use your fingers and the bottom of a dry measuring cup to help press the mixture into the bottom and up the sides of the dish.