Preheat oven to 350°F (175°C).
Line an 8×8 inch baking pan with parchment paper, leaving an overhang on the sides.

Prepare the Crust:
In a medium bowl, combine graham cracker crumbs and granulated sugar.
Pour in the melted butter and mix until well combined and the crumbs are evenly moistened.
Press the mixture evenly into the bottom of the prepared baking pan.
Bake for 8-10 minutes until lightly golden. Remove from oven and let cool slightly.

Prepare the Pumpkin Filling:
In a large bowl, beat the softened cream cheese with an electric mixer until smooth and creamy.
Gradually add the granulated sugar and beat until well combined.
Beat in the pumpkin puree until smooth.
Add the eggs one at a time, beating well after each addition.
Stir in the vanilla extract, cinnamon, ginger, cloves, and nutmeg.
Pour the pumpkin filling evenly over the baked crust.

Bake the Bars:
Bake for 30-35 minutes, or until the edges are set and the center is mostly firm (it will continue to set as it cools).
If adding a streusel topping, sprinkle it over the filling during the last 10-15 minutes of baking.

Cool and Chill:
Let the bars cool completely in the pan on a wire rack.
Once cooled, cover the pan and refrigerate for at least 2-4 hours, or preferably overnight, to allow the cheesecake to set fully.
Once chilled, use the parchment paper overhang to lift the bars out of the pan.
Cut into squares or bars.

Serve:
Serve chilled. Drizzle with caramel if desired.