6 yams or sweet potatoes, cooked & cooled
3 navel oranges, do not peel
1 1/2 sticks butter
3/4 c. sugar
1 c. orange juice
1/4 c. Grand Marnier liqueur
2 tbsp. lemon juice
Another 1/4 c. of Grand Marnier liqueur for sprinkling on layers

Preheat oven to 375 degrees. Peel and slice potatoes thinly. Place in shallow buttered baking dish. Top with layer of orange slices. Dot with butter. Sprinkle with sugar and liqueur. Continue layering until there are 3 layers. Mix orange juice, lemon juice, and liqueur. Pour over potatoes. Bake until syrup forms and top is browned, about 1 1/2 hours.

(and if you believe this, you'll believe anything)