Butter a shallow 1 1/2 quart baking dish (oven proof glass (Pyrex) or non-reactive baking pan). Combine hot milk and croutons in a large mixing bowl and let croutons soak for 10 minutes. Add remaining ingredients and mix to combine. Pour mixture into prepared pan. Cover and refrigerate for one hour or overnight. (If casserole has been refrigerated overnight, remove from refrigerator 30 minutes before baking.) Preheat the oven to 325 degrees F. Bake 30 to 35 minutes or until set.