Preheat oven to 400 degrees.
Prepare double crust pie pastry according to directions. Line a shallow pie pan with one pie crust.
Combine raisins and water in a saucepan and boil for 5 minutes, then turn heat to low. Mix together brown sugar, cinnamon, nutmeg and salt, and add to raisins. Add in corn starch slurry. Continue cooking an additional 2-3 minutes, stirring constantly. Remove from heat and stir in vinegar and butter.
Pour cooked filling onto pie crust, cover with second pie crust. Seal edges together and be sure to cut slits to vent the top crust.
Bake at 400 degrees for 25-30 minutes, until pie crust turns golden brown.
Serve warm with ice cream or whipped topping.
