Remove from the heat and stir in the vanilla and optional vodka (vodka doesn’t freeze, which will help keep your sorbet from becoming a block of ice after freezing. It isn’t totally necessary, but it helps).
Transfer the mixture to a blender and pulse for a few seconds to fully combine the ingredients. Then, move to the refrigerator until well chilled.
Follow your ice cream maker’s instructions to make the sorbet. Depending on how it looks when finished, you may be able to eat it right away (I dare you not to!) or you can chill it further until it develops the perfect consistency.
Variation: Add a few drops of peppermint oil when adding the vanilla for Mint Chocolate Sorbet. I’ve tried both and they’re each amazing in their own right. If you like peppermint, you’ll love the mint version.
Without an Ice Cream Maker…
Just like above, heat the water, cocoa powder, salt, and sugar in a saucepan. Except this time, use only 1 1/2 cups water. Remove from the heat and stir in the chocolate chips and vanilla. Then freeze this mixture into chunks (possibly an ice cube tray).
Once the chunks are frozen, add them to a blender with 3/4 cup cold water (and optional tablespoon of vodka). Blend until smooth and freeze again, stirring every 30-60 minutes. After a few hours in the freezer, you should have something similar to the end result from the ice cream maker.