Preheat oven to 400˚F (200˚C) and place the sweet potatoes on large rimmed baking sheet.
Poke each sweet potato a few times with a fork and bake in the preheated oven until tender through the thickest part, 35-45 minutes. Allow to cool until able to handle.
Peel and place sweet potatoes in large food processor. Process until smooth, scraping down the sides as needed.
In a small saucepan, place the cream, brown sugar, butter, and a large pinch of salt over medium heat. Scrap and whisk in the seeds from the vanilla bean and add the pod to the cream. Once simmering and the brown sugar has completely dissolved, remove from heat and discard the vanilla bean pod.
Turn on the food processor with pureed sweet potatoes and slowly pour in the cream. Add any vanilla bean seeds that remain in the pan. Season to taste with salt as needed.
Serve immediately (dusted with cinnamon if desired) or allow to cool to room temperature, store in an airtight container, and refrigerate for up to a day.