Put the cranberries in a large pot with the water and sugar. Bring the water to a boil and simmer for about 15 minutes. Allow the mixture to cool, and add the beaten egg and butter.
Bake the bottom layer of the pie shell at 400◦F (200◦C) for 10 minutes. Remove the crust from the oven and allow it to cool. Once it has cooled, fill the pie crust with the cranberry mixture.
Return the pie to the oven and bake for another 35-40 minutes at 350◦F (180◦C).
Serve with fresh or whipped cream.
Variation: This pie may be covered with woven strips of pastry dough, according to an old Acadian tradition. To vary the taste, 1 tsp. (5 ml) of vanilla may also be added to the cranberries. Pie crust recipe here.