In a medium sauce pan heat the cream over medium heat until it starts to steam.
Pull the pan off the heat and add the chopped chocolate and peanut butter. Let the mixture sit for 30 seconds.
Whisk the cream, chocolate, and peanut butter together until the mixture is smooth.
Add the powdered sugar and mix until smooth.
Add the vanilla and salt and mix to combine.
Allow the mixture to cool for about 10 minutes before serving warm. The mixture will thicken slightly as it cools and will be a nice texture when it hits the cold ice cream.
Store any extras in an air-tight container in the fridge and reheat to warm before serving again.
Notes
Sometimes my powder sugar will be a bit clumpy which isn't the dream. I've found it best to sift it into the bowl of liquid chocolate and cream while whisking or to have the powdered sugar in a separate bowl and then slowly pour the chocolate mixture into the powdered sugar while whisking. You'll get a smoother product by doing one of these methods opposed to just plopping in the powdered sugar and then stirring it in.