How to Make It
In a medium saucepan, combine the papaya, pineapple juice, water, sugar, lime juice, chiles, peppercorns, allspice, cinnamon stick, fennel and coriander; bring to a boil. Reduce the heat to moderately low and cook, stirring occasionally, until the papaya just begins to fall apart, about 20 minutes.
Strain the syrup through a fine sieve, pressing on the papaya to puree it. Return the puree to the saucepan and add the cornstarch mixture. Bring to a boil, then cook over moderate heat until thick, about 5 minutes.