Preheat oven to 350°. In a large saucepan, bring stock to a boil. Slowly stir in grits. Reduce heat to medium-low; cook, covered, about 5 minutes or until thickened, stirring occasionally. Remove from heat. In a small bowl, stir a small amount of hot grits into egg substitute; return all to pan, mixing well., Add process cheese, milk and butter; stir until cheese is melted. Stir in ham, green onions and seasonings. Transfer to a greased 11x7-in. baking dish. Sprinkle with cheddar cheese., Bake, uncovered, 35-40 minutes or until edges are golden brown and cheese is melted. Let stand 10 minutes before serving.