Potato Souffl�

2 pounds potatoes, peeled and cut into 2-inch pieces
3 tablespoons butter
1 small onion, finely chopped
2 tablespoons sour cream
2 eggs, separated
2 tablespoons heavy cream
Salt and pepper, to taste
1 tablespoon dried parsley, thyme, or tarragon
4 ounces grated Parmesan cheese

In a saucepan, cook the potatoes in boiling salted water until tender, 12 to 15 minutes. Drain and mash. In a small pan over medium heat, combine the butter and onions and cook until the onions are soft, 4 to 5 minutes. Add the onions to the mashed potatoes, then stir in the sour cream, egg yolks, and cream. Season to taste with salt and pepper. Add the herbs and grated cheese and stir until smooth.

In a small bowl using an electric mixer, beat the egg whites until stiff. Carefully fold two tablespoons of egg white into the potato mixture to loosen it, then gradually fold in the rest. Pour into a well-greased 7-inch souffl� dish and bake in a preheated 350�F oven until top is golden brown, about 25 to 30 minutes (check after 15 minutes).

Serves 6 to 8.