1. In a large pot, cook sweet potatoes in water until tender.
2. Drain and let them cool down enough to handle comfortably.
3. Peel and mash.
4. Preheat oven to 375 degree F.
5. In a large bowl, mix together mashed sweet potato, butter, orange juice, brown sugar, salt and 1 cup pineapple.
6. Grease a 1 1/2-quart casserole with butter.
7. Into the well-greased 1 1/2-quart casserole, place the mixture and top with remaining pineapple.
8. Place the dish in the oven and bake for 30 minutes.