To make pumpkin purée from scratch, peel & cut the pumpkin in dices. Scrape out the insides (you kan save the pumpkins seeds to toast) and discard. On a low to medium heat, simmer the pumpkin in the evaporated milk, add the sugar and spice while simmering (about 1 hour). Let the mixture cool down (even better when you put it in the fridge for a night).Beat the eggs and mix them in the cooled pumpkin puréePreheat your oven to 425°F (220 °C).Line a baking dish with the store bought pie crust. Pour in the filling and bake at a high temperature of 425°F (220 °C) for 15 minutes. Then after 15 minutes, lower the temperature to 350°F (180 ° C). Bake for 45 to 55 minutes more, or until a knife inserted in the center comes out clean.Cool the pumpkin pie on a wire rack for 2 hours.Serve with whipped cream or some sugared pecans.