1. Preheat your oven to 350°F. Line a 9×9-inch baking pan with parchment paper, leaving some overhang on the sides for easy removal later.

2. In a bowl, combine the graham cracker crumbs, melted butter, and granulated sugar until the mixture resembles wet sand. Press this mixture firmly into the bottom of the prepared baking pan. Bake for 10 minutes, then let it cool.

3. In a mixing bowl, beat the softened cream cheese and granulated sugar until smooth and creamy. Add the eggs one at a time, mixing just until incorporated after each addition, then blend in the vanilla extract.

4. Spread about half of the cheesecake mixture evenly over the cooled graham cracker crust.

5. In a separate bowl, whisk together the pumpkin puree, pumpkin pie spice, and light brown sugar until smooth. Gently fold this pumpkin mixture into the remaining cheesecake batter, being careful not to overmix – you want to maintain distinct swirls.

6. Dollop the pumpkin-cheesecake mixture over the first cheesecake layer. Use a butter knife to gently swirl through both layers, making 3-4 passes. Bake the bars in the preheated oven for 35-40 minutes, until the edges are set but the center still has a slight jiggle.

7. Allow the bars to cool completely in the pan, then refrigerate for at least 2 hours (recommended). Use a sharp knife, wiping it between cuts, to slice the bars into neat squares.