Ptrheat oven to 350 degrees. Line a 7 x 11-inch baking dish with foil, then coat foil with non-stick cooking spray. In a medium bowl combine powdered sugar, bourbon, water and vanilla, mix well and set aside.
Season the pork tenderloins with salt and pepper, place in the baking dish. Spoon half of the sugar mixture over the pork and roast for 1 hour. Remove from the oven and spoon the remaining sugar mixture over the tenderloins. Roast for 10 minutes more or until no pink remains. Cut into 1/4-inch thick slices and serve with the sauce from the pan. Makes 4-5 servings.