Preheat oven to 325°F (165°C). Lightly spray a 7×11-inch baking dish. Put 4 eggs a bowl.
Whisk eggs until smooth and frothy.
Add 1 cup brown sugar and whisk until well combined.
Whisk in milk, heavy cream, pumpkin.
Add cinnamon, ginger, and allspice and whisk until smooth.
Cut bread into 1/3″ cubes, remove the crust if you like.
Add cubed bread to the prepared baking dish.
Pour the pumpkin custard over it and add the cranberries. Press the bread down gently so it becomes thoroughly soaked. Let stand for 10 minutes.
Bake for 25 minutes.
Remove from the oven and sprinkle the remaining 3 tablespoons brown sugar evenly over the top.
Return to the oven and bake another 20–25 minutes, until the center is set and the top is lightly browned.
Cool on a wire rack for 15 minutes before serving.
Serve warm with vanilla ice cream or whipped cream.