Preheat the oven to 350°F.

Spray a 9-inch square baking dish liberally with nonstick cooking spray. Set aside.

If using raisins, place the raisins and bourbon in a small bowl. Let the raisins soak while you prepare the bread pudding.

Cut the bread into 1-inch cubes and set aside.

In a large mixing bowl, whisk together the eggs, half-and-half, sugar, butter, vanilla extract, cinnamon, and salt until combined. Add the bread cubes and soaked raisins (if using) to the mixture. Fold together with a rubber spatula until bread is thoroughly coated.

Transfer the bread mixture to the prepared baking dish and smooth into an even layer. Cover the dish with aluminum foil.

Bake the bread pudding on middle rack of oven for 30 minutes.

Carefully remove the foil. Continue baking until bread pudding is golden brown on top and a toothpick inserted in the center comes out clean, 15-20 minutes.

Check to see that bread pudding is done. Remove from oven or add time as needed.

If serving warm, allow the bread pudding to cool for at least 15 minutes before plating. To serve cold, chill the bread pudding in the refrigerator for at least 2 hours. Dust with powdered sugar immediately before serving, if desired.