Preheat the oven to 350°F.
Grease a 9x9-inch high-sided casserole dish.
Combine the bread, spinach, and artichokes in a large bowl.
Whisk the milk, sour cream, and eggs in a medium bowl until thoroughly blended.
Pour the custard over the bread mixture and toss, then stir in 6 ounces of brie and the parmesan.
Transfer the mixture to the prepared dish and top with the remaining brie pieces.
Cover the dish with foil and let rest for 30 minutes to hydrate the bread.
Bake covered for 45 minutes, then uncover and bake for an additional 10 minutes.