From my mother’s mother’s recipe book. The soufflé is very rich, so Christmas was the only time of year Grandma ever made it.
3 eggs, separated
1 cup cooked spinach, chopped
1 cup white sauce (recipe follows)
1/4 cup chopped onions
1/2 cup grated cheddar cheese
In a small skillet, sauté onion in butter. In a small bowl of an electric mixer, beat egg yolks until thick and lemon colored. Add yolks a little at a time to white sauce, stirring all the while. Stir spinach and cheese into sauce. In a separate bowl, beat whites until stiff peaks form, then fold whites into spinach mixture. Pour mixture into a greased 8-by-8-inch casserole. Bake at 350 degrees for 50-60 minutes or until soufflé is done.
White sauce
2 tablespoons butter
2 tablespoons flour
1 cup milk or half-and-half
1/2 teaspoon salt
1/8 teaspoon pepper
Over medium heat, melt butter in a small saucepan. When foam subsides, add flour all at once and stir for 1 minute. Gradually add milk to flour mixture, stirring constantly. Add salt and pepper and stir until sauce thickens.

