6 eggs, separated
¼ tsp. cream of tartar
Butter bottom and sides of 2½-quart souffle dish or casserole. Dust with Parmesan cheese.
In large saucepan melt ⅓ cup butter. Blend in flour, onion and mustard. Cook, stirring constantly, over medium-high heat until mixture is smooth and bubbly. Stir in milk all at once. Cook, stirring constantly, until mixture boils and thickens. Remove from heat. Stir in Cheddar cheese until melted.
In small mixing bowl beat egg yolks at high speed until thick and lemon-colored, about 5 minutes. Blend small amount of hot cheese mixture into yolks. Stir yolk mixture into cheese mixture.
Wash and dry beaters. In large mixing bowl beat egg whites and cream of tartar at high speed, until stiff but not dry, just until whites no longer slip when bowl is tilted. Gently but thoroughly fold yolk mixture into whites. Carefully pour into prepared dish. For a “top hat,” hold a spoon upright and circle mixture to make ring about 1 inch from side of dish and 1 inch deep.
Bake in preheated 350° F. oven until puffy, delicately browned and souffle shakes slightly when oven rack is gently moved back and forth, 35 to 40 minutes. Serve immediately.
SWEET POTATO SOUFFLE
6 to 8 servings
¾ C. sugar