With butter, grease a 9-inch x 13-inch ceramic or glass baking dish.
In a large bowl, beat eggs. Whisk in milk, half and half, vanilla extract, nutmeg, and cinnamon.
Working in batches, dip slices of brioche into batter to coat making sure the both sides are coated. Overlap brioche slices in baking dish forming two rows of bread. Pour remaining batter over top. Refrigerate, covered, for at least 2 hours or overnight.
Preheat oven to 375 degrees.
When oven is heated to 375 degrees, covered French Toast dish with foil and bake for 25 minutes. Uncover; bake until top is golden brown and brioche looks crunchy, 20 to 25 minutes more. Once baking is done, remove French Toast Bake from oven and let cool for 5 minutes. Sift a bit of powdered sugar over the top of the French Toast Bake. Next, make the Maple Whipped Cream.
To make the Maple Whipped Cream. Add heavy cream and maple syrup to a mixing bowl. Using an electric mixer, beat the heavy cream mixture on high for 3 to 5 minutes or until stiff peaks are formed. Top the baked French Toast Bake with Maple Whipped Cream and serve. Enjoy!