Grease a 9x13 inch baking dish with butter or non-stick cooking spray.
Place half of the bread cubes into the prepared baking dish in an even layer.
In a small bowl, beat the softened cream cheese, powdered sugar, and 1/2 teaspoon of vanilla extract until smooth.
Drop small spoonfuls of the cream cheese mixture evenly over the bread layer, then top with the remaining bread cubes.
In a large mixing bowl, whisk together the eggs, milk, heavy cream, maple syrup, 1 teaspoon of cinnamon, nutmeg, salt, and the remaining 1/2 teaspoon of vanilla extract.
Pour the egg mixture evenly over the bread cubes, pressing down lightly with a spatula to ensure all bread is submerged.
Cover the dish with plastic wrap and refrigerate for at least 4 hours, preferably overnight.
When ready to bake, preheat the oven to 350°F (175°C).
Prepare the topping by combining the brown sugar, flour, and 1/2 teaspoon of cinnamon in a small bowl; cut in the cold butter using a pastry cutter or fork until crumbly.
Remove the plastic wrap, sprinkle the crumble topping over the casserole, and bake for 45 to 50 minutes until the center is set and the top is golden brown.