How to Make It
Scrape vanilla bean seeds into a blender; add coconut milk, peanut butter, condensed milk, rum, and cinnamon. Process until smooth, about 45 seconds. (Mixture will be the consistency of a milkshake.) Cover and chill until ready to serve, up to 3 days.
Fill 6 lowball glasses with shaved ice (about 1 1/2 cups each), heaping into a mound. Slowly pour peanut mixture over ice (about 1/2 cup each). Garnish with nutmeg, and serve with spoons.