Sweet Potato Pie Recipe

When I was in the states I discovered that americans love their sweet potato pies. I tried a few different versions of this famous pie and loved them all. They serve it up for Thanksgiving and Christmas.
I got this recipe off my friend in Seattle. I have made it several times for friends here and they all loved it. I am sure that once you try it, you will become a fan of this great american traditional pie. You can always substitue the sweet potato for pumpkin if preferred. I would recommend that you use either butternut or jap pumpkin as they are sweeter.
It is easy to make. I have made it using my own shortcrust pastry recipe and also just using the bought frozen ones from the supermarket. Either way, the pie will taste really yummy.
You can always halve this recipe if you only want to make 1 pie but advise making the 2 pies as they will disappear very quickly.

INGREDIENTS:
3 large sweet potatoes - about 1 kilo (2 1/2 lbs)
1 1/2 cups sugar
125g butter (1/2 cup)
4 eggs
1 teaspoon cinnamon
1/2 teaspoon nutmeg
1 teaspoon vanilla essence
1 x 375ml can evaporated milk(12 ounces)
2 x 22 - 24cm (9 inch) shortcrust pie cases

METHOD:
Preheat oven to and a baking tray to 180C (375) or 170C if fan forced oven.
Place potatoes unpeeled in a large pot of water and boil until cooked. Remove and cool slightly by running under cold water. Remove skins from them.
Place potatoes in a large mixing bowl on electric mixer and beat until smooth.
Add butter and sugar and beat well. Beat in eggs, one at a time. Mix in spices, vanilla essence and milk.
Pour into unbaked pasty cases and place on a baking tray, nearer to the middle of your oven.
Bake for approximately 1 hour, then test if cooked. Insert a clean knife into pies and if it comes out clean then you know they are cooked. If not, continue cooking for another 5 -10 minutes and check again.
Remove from oven and let them cool down on a wire rack.
The pies will rise up similar to cooking a souffle but will subside as cooling.
Serve with whipped cream or ice cream.
They are suitable to freeze for up to 3 months.