Preheat your oven to 425°F (220°C). Line a 9x13" baking dish with parchment paper or aluminum foil for easy removal.

In a small bowl, mix the flour and 1/4 cup of sugar. Add the cubed butter and cut it into the flour using a pastry cutter or two forks until it resembles coarse crumbs. You can also use a food processor for this step to save time.

Press the crust mixture into the prepared baking dish evenly. Make sure to spread it out well to ensure even baking.

In a large mixing bowl, combine the pumpkin puree, eggs, salt, pumpkin pie spice, and 2 cups of sugar. Whisk or beat until well mixed. Add the evaporated milk and stir until fully combined.

Pour the pumpkin mixture over the crust in the baking dish. Bake at 425°F (220°C) for 15 minutes. Then, without removing the pan, reduce the oven temperature to 350°F (175°C) and bake for an additional 50-55 minutes, or until the filling is set. Keep an eye on it to avoid overbaking.

Once baked, take the pan out of the oven and let it cool completely on a wire rack. This cooling step is crucial for the bars to set properly. Refrigerate for at least 2 hours, or overnight for best results.

Cut the chilled bars into squares and serve with whipped cream and a sprinkle of cinnamon if desired. Enjoy the delightful taste of fall in every bite!