Combine the cranberries, salt, sugar, and flour, and refrigerate the mixture for one or more hours
Add the butter when you add the cranberry mixture into the pie crust.
Make a lattice pie crust for the top of the pie. Brush the top of the pie crust lattice top with egg.
Preheat oven to (450°F) = (232°C) degrees. Bake the pie for 10 minutes. Then lower the oven to (350°F) = (176°C) degrees and bake another 45 minutes. Serve pie in wedges with vanilla ice cream or whipped cream.