Preheat oven to 400°.
Cut a piece of foil long enough to fit around a 2-quart soufflé dish, allowing a 1-inch overlap; fold foil lengthwise into thirds. Lightly coat one side of foil and bottom of dish with cooking spray. Wrap foil around outside of dish, coated side against dish, allowing it to extend 4 inches above rim to form a collar; secure with string or masking tape.
Remove casings from sausage. Cook the sausage in a large saucepan over medium heat until browned, stirring to crumble. Drain sausage in a colander, and pat dry with paper towels. Wipe sausage drippings from pan with a paper towel.
Bring broth to a boil in pan, and gradually stir in grits. Cover, reduce heat, and simmer 5 minutes, stirring occasionally. Remove from heat; add sausage, mustard, salt, pepper, and cheese, stirring until the cheese melts.
Place egg substitute in a large bowl. Gradually add hot broth mixture to egg substitute, stirring constantly with a wire whisk. Stir in chives; set aside.
Beat egg whites and cream of tartar at high speed of a mixer until stiff peaks form. Gently stir one-fourth of the egg white mixture into the broth mixture. Gently fold in the remaining egg white mixture.
Pour mixture into prepared soufflé dish. Bake at 400° for 10 minutes. Reduce oven temperature to 375°, and bake an additional 55 minutes or until puffed and golden. Carefully remove foil collar, and serve immediately.