To date, the most expensive hot pepper you can buy is the aji charapita, also known as "the mother of all chilis." Originally harvested in Peru, these tiny peppers can cost upward of $300 per pound.

Combine the peppers, mangoes, sugar, salt, ginger, mustard and vinegar in a deep stew pan and cook until the peppers are soft (about 25 minutes). Purée to a smooth batter consistency in a food ...