Preheat oven to 350 degrees F. Grease a 9×13 baking dish with nonstick spray.
In a large bowl combine the eggs, milk, heavy cream, vanilla extract, cinnamon, nutmeg, sugar, and orange zest. Whisk together until well mixed.
Slice each croissant in half creating a top and bottom.
Layer the croissants bottoms in the baking dish. Pour half of the cream mixture over the croissants.
Layer the croissants tops in the baking dish. If needed you can tear the croissant into smaller pieces to ensure they all fits. Pour the remaining cream mixture over the croissants.
Cover the dish and place in the refrigerator for at least 2 hours or overnight.
When ready to bake remove baking dish from the refrigerator and let stand 30 minutes to bring the temperature closer to room temp.
After 30 minutes place the dish in the oven and bake, covered, for 30 minutes. Uncover; continue to bake for an additional 25-30 minutes, or until golden brown.
While the french toast bakes make your cranberry orange syrup.
When the french toast has finished baking remove from oven and let stand for 10 minutes. Pour the cranberry syrup over the french toast before serving.