Preheat oven to 350°F (175°C).
Line an 8×8 inch baking pan with parchment paper, leaving an overhang on two sides.
In a medium bowl, combine graham cracker crumbs, ¼ cup granulated sugar, and melted butter. Stir until evenly moistened.
Press the crumb mixture firmly and evenly into the bottom of the prepared pan.
Bake for 8-10 minutes, or until lightly golden. Remove from oven and let cool slightly.
In a large bowl, beat softened cream cheese with ¾ cup granulated sugar and pumpkin pie spice until smooth and creamy.
Beat in the vanilla extract and pumpkin puree until well combined.
Add the eggs one at a time, beating on low speed just until each egg is incorporated. Do not overmix.
Pour the filling evenly over the pre-baked crust.
Bake for 30-35 minutes, or until the edges are set and the center is almost set (it should still have a slight jiggle).
Let the bars cool completely in the pan on a wire rack.
Once cooled, refrigerate for at least 2 hours, or until firm, before cutting.
Cut into bars and serve, optionally with whipped cream or caramel sauce.