In a bowl, mix together the dry ingredients - flour, baking powder, cinnamon powder, pumpkin pie spice and salt until well mixed.
In another bowl beat well the butter and sugar. Add eggs to this and beat the mixture very well, the eggs should be whisked very well to blend with the butter sugar mixture.
Add pumpkin puree and evaporated milk to the butter, sugar and egg mixture mix everything well and also add vanilla extract, stir well to mix.
Transfer the wet ingredients mixture to the dry flour mixture slowly and mix well to combine the ingredients without forming any lumps. You can use a balloon whisk to mix it nicely.
Preheat the oven to 350 degree Fahrenheit.
Grease a pie pan with butter and transfer the pie batter to the pan. Sprinkle the extra cinnamon powder on top, if using.
Bake for 1 hour and 10 minutes, just make sure to watch after about 55 minutes of baking since oven temperatures can slightly vary for different ovens.
Once the pie is baked, quickly transfer the pan from the oven to avoid the pie from burning.
Allow the pie to cool down, once the pie is cooled enough, refrigerate for a couple of hours.
Slice and enjoy the chilled pumpkin pie which is delicious and smooth!