Grease a 9x13-inch baking pan with butter or cooking spray. Cut the French bread into 1-inch cubes—you should have about 6 cups. Spread half of the bread cubes evenly across the bottom of the prepared pan, pressing them down gently to create a compact base layer that will absorb the custard mixture.

Beat the softened cream cheese with 2 tablespoons of confectioners' sugar and 1 teaspoon of vanilla extract until smooth and creamy, about 1-2 minutes. Drop spoonfuls of this mixture evenly across the bread in the pan—you want roughly 8-10 dollops spread out so they'll distribute when the custard is poured. This creates pockets of richness throughout the casserole.

Layer the remaining half of the bread cubes over the cream cheese dollops, covering them as evenly as possible. The bread doesn't need to be perfectly packed, as it will settle when the custard is poured.

In a large bowl, whisk together the eggs, whole milk, 2 teaspoons of vanilla extract, 2/3 cup of packed brown sugar, and 3/4 teaspoon of ground cinnamon until well combined and the sugar is mostly dissolved. I prefer freshly ground cinnamon here since it gives a noticeably brighter flavor compared to pre-ground spice. Pour this custard mixture evenly over the assembled bread layers.

Cover the pan tightly with plastic wrap or aluminum foil and refrigerate for at least 3 hours, though overnight (up to 24 hours) is ideal. This resting period allows the bread to fully absorb the custard and creates a cohesive, properly textured casserole.

Remove the casserole from the refrigerator and let it sit at room temperature for 15-20 minutes. Meanwhile, preheat your oven to 350°F (177°C). In a small bowl, whisk together 1/3 cup of packed brown sugar, 1/3 cup of all-purpose flour, and 1/2 teaspoon of ground cinnamon. Add the 6 tablespoons of melted and cooled butter and mix with a fork until the mixture resembles coarse crumbs with some pea-sized pieces—this texture is what creates that perfect crunchy topping.

Sprinkle the streusel topping evenly over the casserole, then bake uncovered for 45-55 minutes until the top is golden brown and a knife inserted into the center comes out with just a few moist crumbs—not wet custard, but not completely dry either. The casserole will continue to set slightly as it cools. Let it rest for 5-10 minutes before serving, then dust with confectioners' sugar if desired and serve with maple syrup on the side.