The best pumpkin pie

This is a wonderfully tangy alternative to the standard pumpkin pie - the creme fraiche adds a light and creamy texture.  Adapted from The Traveler's Lunch and Martha Stewart.

Ingredients

For the crust

12 graham crackers/digestive biscuits ground finely
70 g (5 T) butter
40 g sugar

For the filling

1 can/1.5 c pumpkin puree
1.5 c creme fraiche
3 large eggs
1.5 t vanilla
1 t cinnamon
1/2 t nutmeg
1/2 t ginger
pinch cloves
1/2 salt
1/2 c (100g) dark brown sugar
1/2 c (100g) white sugar
1 T cornstarch

Instructions

1) Preheat oven to 175 C.  Combine graham crackers/digestives with sugar and butter, and combine until the mixtures is the texture of wet sand.
2) Press the mixture into the bottom and sides of a 9" pie plate, and bake crust until it is dry and set, about 12 minutes.
3) While the crust is cooking, in a large bowl combine all of the pie filling ingredients except for the sugars and cornstarch.
4) In a small bowl, combine the sugars and corn starch until no lumps remain.
5) Combine pumpkin and sugar mixtures, and pour into parbaked crust.  Lower oven temperature to 160C and bake until the filling is puffed and set, about an hour.