Potato Puff

My mom sometimes makes this for holiday dinners in place of mashed potatoes -- it's a lot like mashed potatoes but it can be made a day ahead. Source: The Complete Family Cookbook.

3 cups mashed potatoes
4 Tbsp. hot milk
2 beaten egg yolks
4 Tbsp. melted butter
2 stiffly beaten egg whites
2 tsp. grated onion
4 Tbsp. chopped parsley
2 tsp. salt
1/8 tsp. pepper

In bowl, combine potatoes, milk, egg yolks, butter, onion, parsley and salt and pepper. Fold in egg whites. Pile in a greased casserole. Bake 350°F for about 40 minutes, until brown.

Serves 6.