In a saucepan, bring water to a boil. Slowly stir in grits. Reduce heat; cook and stir for 4-5 minutes or until thickened. Add cheese and garlic powder; stir until cheese is melted. Pour into greased 2-cup baking dish.
In a small bowl, combine cornflakes and butter; sprinkle over grits. Bake, uncovered, at 350° for 10-15 minutes or until firm and top is lightly toasted.