• Place the bowl of a stand mixer, the whisk attachment, and the can of evaporated milk in the freezer for at least 30 minutes. Do not skip this step.

Crust

• Lightly spray a 9x13-inch baking dish with nonstick cooking spray.
• In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter until evenly moistened. Reserve ¼ cup of the crumb mixture for the topping.
• Press the remaining crumb mixture firmly into the bottom of the prepared pan. Set aside.

Filling

• In a medium bowl, beat together the cream cheese, peanut butter, sugar, vanilla, and salt until smooth and creamy, about 2 to 3 minutes.
• In a separate bowl, whisk the gelatin into the boiling water until completely dissolved, about 1 to 2 minutes. Stir in the cold water. Refrigerate for a few minutes while whipping the evaporated milk, but do not let the gelatin begin to set.
• Pour the chilled evaporated milk into the cold stand mixer bowl. Using the whisk attachment, beat on high speed until soft peaks form, about 5 minutes.
• With the mixer on low, slowly pour in the gelatin mixture. Mix for about 30 seconds.
• Add the peanut butter mixture and mix on low just until combined, about 20 to 30 seconds. Do not overmix.
• Pour the filling over the prepared crust and spread into an even layer. Sprinkle the reserved graham cracker crumbs evenly over the top.
• Cover and refrigerate for at least 12 hours, or overnight, before cutting and serving.