Vinegar Pie

Sift flour and salt together into a large mixing bowl. Rub shortening and butter into flour mixture with your fingers until dough resembles coarse cornmeal. Add egg, then 4 tablespoons ice water, 1 tablespoon at a time, and mix until dough holds together. Cover with plastic wrap and refrigerate 1 hour. For the filling, beat eggs with a whisk in a large mixing bowl. Add flour, sugar, butter, vinegar, vanilla, raisins, cinnamon, nutmeg and sour cream. Stir just until mixed. Preheat oven to 300 °F (150 °C). Roll out dough into a 12-inch round on a floured work surface. Ease dough into a 9-inch pie pan and crimp edges. Add filling and bake until top is golden, about 1 hour. There will be tiny bubbles on the surface, but filling should not wiggle when pan is shaken. Serve warm, or refrigerate and serve cold. Top with whipped cream if desired.