Holiday Candied Pineapple Sweet Potatoes

Preheat oven to 350 degrees. Line a sheet pan with foil. Place the sweet potatoes on the prepared pan. Bake about 90 minutes until tender. Cut in half and scoop the sweet potato out of the skins. Place the sweet potato in a large bowl. Add pineapple juice, margarine, salt and pumpkin pie spice and beat until fluffy. Grease the inside of a 13x9 inch baking dish. Transfer the sweet potato mixture to the prepared dish. Sprinkle the potato mixture with the brown sugar and top with pineapple rings. Bake about 20 minutes until heated through. Serve hot.