Preheat oven to 350 degrees F. Grease a 2-quart casserole with 2 tablespoons of butter.
Combine remaining 1/4 cup butter, water, and salt in a heavy medium saucepan over medium heat. When mixture comes to a simmer, add the grits, stirring until thoroughly combined. Continue to cook the grits at a simmer, stirring frequently, until thickened, about 15 minutes.
Meanwhile whisk together egg, cream and pepper. Stir into cooked grits along with cheese. Pour mixture into prepared casserole. Bake until set, about 45 minutes. Remove from the oven and let stand about 5 minutes before serving.