Mashed Potato Souffle

Directions

1. 1
   In a large bowl combine mashed potatoes, heavy cream, onion and 1 teaspoon salt.
2. 2
   Into the potato mixture, beat in the stick of softened butter, 2 egg yolks and salt and white pepper to taste.
3. 3
   In another bowl beat the 4 egg whites with a pinch of salt and cream of tartar until stiff peaks form.
4. 4
   Fold this into the potato mixture.
5. 5
   Put the souffle into a buttered 1 to 1 1/2-quart casserole.
6. 6
   Top it with the onion slices, brush it with butter and bake it for 45 minutes.
7. 7
   Serves 8.
8. 8
   This recipe should not be doubled.