Generously grease three 10-ounce casseroles with butter. Carefully break 2 eggs into each casserole; sprinkle with chives, salt, and pepper. Set casseroles in a 13x9x2-inch baking pan; place on an oven rack. Pour hot water around casseroles in pan to a depth of 1 inch.
Bake in a 325 degree F oven for 20 minutes. Sprinkle cheese on top of eggs. Bake for 5 to 10 minutes more or until eggs are cooked and cheese melts. Makes 3 servings.