1. Preheat your oven to 350°F (175°C) and line a 9×13-inch baking dish with parchment paper, leaving some overhang for easy removal.
2. In a medium bowl, mix together the flour, granulated sugar, brown sugar, and salt. Stir in the melted butter until combined and crumbly.
3. Press the mixture firmly into the bottom of the prepared baking dish to form the crust. Bake for 15 minutes, or until lightly golden.
4. While the crust is baking, prepare the pumpkin filling. In a large bowl, whisk together the pumpkin puree, evaporated milk, eggs, vanilla extract, pumpkin pie spice, and ground cinnamon until smooth.
5. Pour the pumpkin mixture over the pre-baked crust, spreading it evenly with a spatula.
6. Bake for 40-45 minutes, or until the filling is set and a toothpick inserted into the center comes out clean.
7. Allow the bars to cool completely in the pan before lifting them out using the parchment paper overhang. Cut into squares and serve with a dollop of whipped cream if desired.

One of my favorite memories is baking these bars with my abuela. She taught me to check the doneness by gently shaking the pan to see if the filling jiggles just right. It’s a small detail, but it makes all the difference.