Prep the pan: Heat the oven to 325°F (165°C). Line a 9x13-inch pan with parchment, leaving overhang on the long sides for easy lifting. Lightly grease the parchment.

Make the crust: In a bowl, combine graham crumbs, brown sugar, cinnamon, and salt. Stir in melted butter until the mixture looks like damp sand.

Press and par-bake: Firmly press the crust into the pan in an even layer. Bake for 8–10 minutes, until lightly set and fragrant. Cool for 5–10 minutes while you make the filling.

Beat the cream cheese: In a large bowl, beat cream cheese on medium speed for 2 minutes until very smooth, scraping the bowl. Add granulated and brown sugars; beat 1 minute more until fluffy.

Add eggs and flavor: Beat in eggs one at a time on low, just until incorporated. Mix in vanilla and sour cream.

Finish the filling: Add pumpkin puree, flour, cinnamon, ginger, nutmeg, cloves (if using), and salt. Mix on low until smooth and fully blended, scraping the bowl as needed.

Fill the pan: Pour the filling over the warm crust and smooth the top with a spatula. Tap the pan gently on the counter to release air bubbles.

Bake: Bake at 325°F (165°C) for 35–42 minutes, until the edges are set and the center has a slight wobble. Avoid overbaking.

Cool gradually: Turn off the oven, crack the door, and let the pan sit inside for 10 minutes. Transfer to a rack and cool to room temperature.

Chill: Cover and chill for at least 4 hours, preferably overnight, to set fully.

Slice and serve: Lift out with the parchment, slice into bars with a sharp knife, wiping the blade between cuts. Add whipped cream, caramel, or nuts if you like.