Prepare the Pan & Crust: Preheat oven to 300°F.
Line a 9×13-inch baking dish with parchment paper or foil, leaving an overhang on two sides for easy lifting later. Tip: Even if you spray with nonstick spray, the bars can stick—so lining is highly recommended.
In a medium bowl, combine 1 ⅔ cups graham cracker crumbs (about 13 whole graham crackers, finely crushed)with ¼ cup melted unsalted butter and 2 tablespoons granulated sugar. Stir until evenly combined.
Press the mixture firmly into the bottom of the prepared pan to form an even crust. Set aside.
Make the Cheesecake Filling: In a large mixing bowl (or stand mixer with paddle attachment), beat 4 packages (8 ounces each) of softened cream cheese with 1 ½ cups granulated sugar on low speed until smooth and fluffy.
Add 4 large eggs, one at a time, mixing just until combined after each addition. Do not overmix.
Mix in 1 cup canned pumpkin puree (not pumpkin pie filling) and 2 teaspoons pumpkin pie spice until smooth.
Assemble & Bake: Pour the pumpkin cheesecake filling over the crust and spread it into an even layer.
Bake for 50–55 minutes, or until the edges are set and the center is slightly jiggly.
Turn off the oven, crack the oven door open, and let the cheesecake bars cool slowly for 60–90 minutes. This helps prevent cracks from forming.
Chill & Serve: Cover lightly and refrigerate for at least 3 hours (overnight is best) to fully set.
Use the parchment/foil overhang to lift the cheesecake from the pan before cutting into squares.
Garnish with whipped cream and a sprinkle of pumpkin pie spice before serving.