Prep the pan. Line a 9x9-inch square baking pan with parchment, letting it hang over the sides for easy lifting. Preheat the oven to 350°F (175°C).
Make the crust. Stir graham crumbs, melted butter, sugar, and salt until evenly moistened. Press firmly into the pan, packing it tight with the bottom of a measuring cup.
Bake for 8–10 minutes until lightly set. Cool for 5 minutes while you mix the filling.
Beat the cream cheese. In a large bowl, beat softened cream cheese on medium speed until completely smooth and fluffy, about 2 minutes. Scrape the bowl.
Add sugars and pumpkin. Beat in granulated and brown sugar until creamy.
Mix in pumpkin puree until fully combined. Scrape the bowl again.
Add eggs and flavorings. Beat in eggs one at a time on low speed, just until combined. Mix in vanilla, spices, salt, and cornstarch.
Do not overmix—this keeps air out and prevents cracks.
Assemble the layers. Pour the filling over the warm crust and smooth the top. Warm the caramel slightly if thick, then dollop teaspoons over the surface. Use a skewer or butter knife to gently swirl it into the batter. Don’t over-swirl or it will blend in and disappear.
Bake low and slow. Reduce oven to 325°F (165°C).
Bake 35–42 minutes, or until the edges are set and the center wobbles slightly like Jell-O. The top should look matte, not wet.
Cool gradually. Turn off the oven, crack the door, and let the bars sit inside for 10 minutes. Move to a rack and cool to room temperature, about 1–2 hours.
Chill to set. Cover and refrigerate for at least 4 hours, preferably overnight.
This step is key for clean slices and creamy texture.
Finish and serve. Lift out using the parchment and cut into 16–20 bars with a sharp knife, wiping between cuts. Drizzle with more caramel and a pinch of flaky sea salt. Add whipped cream or toasted nuts if you like.