Butter 1-1/2-qt. shallow baking dish; then arrange bread slices in bottom of dish. Whisk eggs, milk, Parmesan, mustard, salt, and pepper in mixing bowl until smooth. Pour egg mixture over bread and press bread into mixture. Let stand at least 15 minutes or refrigerate covered overnight. Heat oven to 350°. Sprinkle scallions over top of bread. Bake 25 minutes. Scatter bacon and tomato over scallions and continue baking until puffed and edges are golden, about 10 minutes longer. Let stand 5 minutes before serving. Nutritional value: 642 cal, 34 g prot, 22 g fat, 80 g carb, 1405 mg sod brunch 3