Using a bit of oil, fry the diced bacon until crispy. Chop the scallions.
In a bowl, whisk together the eggs, milk, salt, and pepper. Add the bread, bacon, scallions, and half of the grated cheese and mix well. Cover and let it sit for about 15 minutes.
Grease an oven-safe baking dish with some butter.
Pour the bread mixture into the prepared dish, cover with aluminum foil, and bake for 25 minutes. Then, remove the foil, top with the remaining cheese, and bake for another 15 minutes.