6 sweet potatoes, fully cooked and cooled
3 navel oranges, peeled and thinly sliced
1/2 to 3/4 c. butter (1 to 1 1/2 sticks)
3/4 c. sugar
1 c. fresh orange juice
2 tbsp. fresh lemon juice, or more to taste

Preheat oven to 375 degrees. Peel and slice the sweet potatoes over thin; place a single layer in a shallow buttered baking dish. Top with a layer of orange slices. Dot generously with butter and sprinkle with sugar. Continue layering. You should have 3 layers, ending with a layer of sweet potatoes, butter and sugar.

Mix the orange juice with the lemon juice and pour over the potatoes. Bake until a pleasant syrup has formed and the top is tinged with brown, about 1 1/2 hours. Can be made ahead and refrigerated. Serves 6-8.