Bring 7 cups water to a boil in a large saucepan; gradually stir in grits. Cover, reduce heat, and simmer, stirring occasionally, 10 minutes. Remove from heat; let stand 15 minutes. Stir in egg yolks, cheese, and next 3 ingredients until smooth.
Beat egg whites at high speed with an electric mixture until stiff peaks form. Fold into grits mixture. Spoon into a lightly greased 3-quart baking dish.
Bake at 275° for 1 hour or until set.