Over medium heat, combine the half and half and sugar. Mix the cornstarch with whiskey in a small bowl and whisk to blend until the mixture is smooth. Add whiskey mixture into the cream mixture and bring to a boil.
Lower heat and simmer for 5 minutes, stirring constantly. Remove the sauce from the heat, add the salt and stir in the butter.
Pour warm sauce generously over the top of the beignet bread pudding.