Step 1: Preheat your oven to 350°F (175°C) and generously butter a 9×13 inch baking dish.
Step 2: Cut the bread into 1-inch cubes and place them in a large mixing bowl along with the fresh cranberries.
Step 3: In a separate medium bowl, whisk together the eggs, sugar, orange zest, orange juice, vanilla, cinnamon, and salt until well combined.
Step 4: Slowly pour in the whole milk and heavy cream, whisking until the custard base is smooth and the sugar has dissolved.
Step 5: Pour the custard mixture over the bread and cranberries. Use a spatula to gently press down on the bread cubes to ensure they are all submerged.
Step 6: Let the mixture sit at room temperature for at least 30 minutes, or cover and refrigerate overnight for best results.
Step 7: Transfer the mixture to the prepared baking dish and sprinkle the top with coarse sugar.
Step 8: Bake for 45 to 55 minutes, or until the top is golden and the custard is set but still has a slight jiggle in the center.
Step 9: Remove from the oven and let cool for 10-15 minutes before serving warm.