1. Wash potatoes; don't peel. Boil in water (enough to cover potatoes) until barely soft (15 min). Drain, cool, peel. Slice into a greased casserole. 2. Preheat oven to moderate (350 degrees F). 3. Bring to a boil brown sugar, water, butter, and raisins. Add cognac and pour mixture over potatoes. 4. Bake uncovered, 30 min, basting several times with syrup in casserole.