In a medium bowl, add brown sugar. Scrape seeds from the vanilla bean, flour, cinnamon, salt, and cayenne pepper into the brown sugar and whisk all ingredients until well incorporated.
Add eggs to the brown sugar mixture. Add syrup, vinegar, and butter to eggs and brown sugar mixture and incorporate until well blended.
Pour peanuts into the fully baked pie crust. Pour filling over the peanuts and shake just a bit to get rid of any air bubbles in the mixture.
Bake pie for about 40 minutes or until set. Remove from oven and allow to cool for at least 10 minutes. Serve with ice cream or vanilla whipped cream.