Lightly coat a 9×13-inch baking dish with non-stick cooking spray.

In a large bowl, beat together the room temperature softened cream cheese, confectioners’ sugar, 2 tablespoons milk, and 1 teaspoon vanilla extract until smooth. Gently fold in 1 cup of the fresh blueberries. (Tip: If you need to increase the spreadability of the cream cheese filling, either add more milk, or microwave it for 20 seconds before spreading over the bread.)

Spread half of the cubed bread in the bottom of the baking dish. Dollop and spread the blueberry cream cheese mixture over the bread. Top with the remaining bread cubes.

In the same large bowl (no need to wash it), whisk together eggs, 2 cups milk, cinnamon, nutmeg, and the remaining teaspooon of vanilla extract.

Evenly pour the egg mixture over the bread layers, pressing gently to make sure all of the pieces are wet. Sprinkle the top of the casserole with the remaining cup of blueberries. Cover tightly with foil or plastic wrap and refrigerate for at least 8 hours for that essential overnight soak.

Pull the casserole out of the fridge and let it sit at room temperature for 30 minutes to an hour. Preheat the oven to 375°F. Cover the casserole with aluminum foil, and bake for 45 minutes. Then remove the foil and continue baking another 30 minutes, or until golden brown and the center is set.

While the French toast bake is in the oven, combine the sugar, water, and cornstarch in a small saucepan. Bring to a boil, reduce heat, and cook for 3-4 minutes while stirring. Add the blueberries and cook on low about 10-15 minutes, until all or almost all of the blueberries have popped. Stir in the butter.

Spoon warm homemade blueberry sauce over the individual servings.