Make the crust: In a medium bowl, stir together the graham cracker crumbs, 1/2 cup melted butter, 1/4 cup granulated sugar, and 1/4 teaspoon salt until the mixture looks like damp sand and holds together when pressed.
Press the crust mixture firmly and evenly into the bottom of the prepared glass dish. Use the bottom of a measuring cup or a flat glass to really pack it down so it bakes up sturdy enough to hold the glossy pecan layer.
Toast the pecans for more flavor: Spread 2 cups of pecans on a baking sheet and toast in a 350°F (175°C) oven for 6–8 minutes, until fragrant and slightly darkened. Let them cool slightly, then roughly chop, keeping some pieces larger for that rustic, pecan-studded look on top.
Preheat the oven to 350°F (175°C) if you turned it off after toasting the pecans. The bars will bake briefly before chilling so the sweetened condensed milk layer can thicken and set properly.
