Preheat the oven to 350°F (175°C). Grease a 9-inch pie dish lightly with butter or nonstick cooking spray.

In a large mixing bowl, whisk together the pumpkin puree, sugar, eggs, evaporated milk, vanilla extract, pumpkin pie spice, cinnamon, salt, and flour until smooth and well combined.

Pour the mixture into the prepared pie dish and smooth the top with a spatula.

Bake for 50 to 60 minutes, or until the center is set and a knife inserted near the middle comes out mostly clean.

Remove from the oven and let the pie cool completely on a wire rack, then refrigerate for at least 2 hours before serving.

Slice and serve chilled or at cool room temperature.