In a medium bowl, combine the flour and salt. Cut in the cold butter pieces until crumbly. Gradually add 3 to 5 tablespoons of ICE water (start with 3 and add more, as needed)- tossing with a fork until the dough holds together when pressed. Don't add too much water. Wrap in plastic wrap and refrigerate for 1 hour (or more, if needed).
Roll out the pie crust dough onto a lightly floured surface into an 11-inch circle. Gently move the rolled pie dough to a 9-inch pie plate. Trim and pinch the edges decoratively. Refrigerate the pie crust while you make the filling.
PREPARE THE FILLING:
Place the sweet potatoes in a medium pot, and cover with water. Bring to a boil. Reduce the heat; cook, uncovered, until tender- 12 to 15 minutes. Drain the potatoes and mash until very smooth. Cool to room temperature.
Preheat the oven to 425 degrees F.
In a large bowl, use an electric mixer to combine the butter and sugar. Mix in the eggs. Add the evaporated milk, TWO CUPS of the sweet potatoes and all of the remaining ingredients; mix well. Pour into the chilled pie shell.
BAKE THE PIE:
Bake at 425 for 15 minutes. Then reduce the heat to 350 and bake 35 to 40 minutes longer- until it is no longer jiggly in the middle and a sharp knife inserted into the center comes out clean. Cool. Store in the refrigerator until ready to serve.
Notes
This pie is delicious to serve on its own. It can also be served with lightly sweetened whipped cream.