Heat oven to 350 degrees. Butter 2 quart baking dish.
Whisk eggs with milk in a bowl; set aside.
Arrange torn croissants over the bottom of the buttered baking dish. Sprinkle with the bacon or crumbled sausage pieces and tomatoe slices. Top with pepper jack cheese OR cheddar cheese, if preferred; then pour the egg mixture evenly over the top. Sprinkle with salt and pepper. Bake 35 to 40 minutes until puffy and lightly browned. Serves 4 to 6.