How to Make It
In a medium saucepan, combine the chopped cranberries with the light brown sugar, orange zest, salt and 2 tablespoons of water and bring to a boil. Simmer over moderately high heat, stirring occasionally, until the cranberries are soft and the sauce is ruby-colored, 3 to 5 minutes. Remove the cranberry mixture from the heat and whisk in the butter and heavy cream. Cook over moderately low heat, whisking, until the butter is completely melted and the sauce is hot, about 3 minutes. Discard the orange zest. Keep the cranberry sauce warm over very low heat.
Preheat the oven to 225°. In a large baking dish, whisk the eggs with the heavy cream, light brown sugar, vanilla extract and salt. Heat a large cast-iron griddle and lightly butter it. Working in batches, dip half of the brioche slices in the egg mixture, turning them, until they are well-moistened. Transfer the soaked brioche to the griddle and cook over moderate heat, turning once, until the French toast is golden and cooked through, about 4 minutes. Transfer the French toast to a baking sheet, cover loosely with aluminum foil and keep warm in the oven. Repeat with the remaining brioche slices. Serve the French toast with the cranberry sauce and whipped cream.