Preheat oven to 350 degrees.
Prep a 6 cup baking dish with nonstick baking spray.
Combine raisins and whiskey in a small bowl.
Cover the raisins and whiskey.
Let stand 10 minutes or until soft.
Do not drain the whiskey from the raisins.
Add the croissants to the prepared baking dish.
Sprinkle 3/4 cup of the raisins throughout the torn croissants. (Raisins and whiskey used to soak the raisins)
Whisk the half and half, eggs, sugar, lemon zest, salt, and vanilla in a large.
Pour this mixture over the croissant pieces.
Ensure all of the croissants pieces have been moistened.
Sprinkle the remaining raisins(1/4 cup) on top of the bread pudding.
Set aside for 25 minutes allowing the bread pudding to soak in the egg mixture.
Sprinkle sugar on the top of the bread pudding.
Bake at 350 degrees for 50 minutes.
Check for doneness by testing with a knife inserted in the middle of the bread pudding.
Set aside for 15 minutes for it to cool.