1-Prepare Oven and Pan: Preheat your oven to 350°F (175°C). Line a 9×13-inch baking pan with foil or parchment paper and lightly grease it to ensure easy removal of the bars.

2-Make the Crust: Process the graham crackers into fine crumbs using a food processor or by crushing them in a sealed bag with a rolling pin.

In a bowl, combine the graham cracker crumbs with granulated sugar and melted butter. Add the optional brown sugar and salt for more depth if desired.

Press the mixture firmly and evenly into the bottom of the prepared pan. For best results, use the base of a measuring cup or glass to compact the crust solidly.

Bake the crust for 10-15 minutes until golden and fragrant, then remove and let it cool slightly.

3-Prepare the Filling: In a medium bowl, whisk together pumpkin puree, pumpkin pie spice, cinnamon, and flour.

In a large bowl, beat cream cheese and sugar until smooth and creamy.

Add vanilla, sour cream, and salt to the cream cheese mixture and beat to combine.

Beat in eggs one at a time, mixing each just until incorporated to avoid overmixing, which can cause cracks.

4-Assemble and Bake: Stir about 1½ cups of the plain cream cheese mixture into the pumpkin mixture until smooth.

Alternately drop spoonfuls of the pumpkin filling and the remaining plain cream cheese filling over the prepared crust.

Use a knife to gently swirl the two mixtures to create a marbled effect, being careful not to cut into the crust.

Bake the assembled bars for 35-45 minutes until the edges are set but the center still jiggles slightly.

5-Cool and Chill: After baking, turn off the oven and crack the door open. Allow the bars to rest in the oven for about 1 hour; this slow cooling helps avoid cracks.

Remove the bars and cool them to room temperature on a wire rack.

Refrigerate and chill for at least 8 hours or overnight to let flavors meld and texture set properly.

6-Serving: Lift the bars from the pan using the foil or parchment paper edges. For clean slices, use a sharp knife heated in hot water and dried between cuts.

Optional garnishes include whipped cream and a sprinkle of cinnamon or pumpkin pie spice.