Soak the purple corn in the 10 cups of cold water overnight. Transfer the corn to a large pot and measure the soaking liquid. Add enough water to make 15 cups. Pour the liquid back over the corn, and add the pineapple, quince, cinnamon sticks, cloves, lemon juice and sugar. Bring to a boil, reduce the heat, and simmer for 2 to 2 1/2 hours.
Remove from the heat, remove the corn cobs and strain the mixture, pressing against the strainer with a spoon to extract all the juice from the fruits and spices. There should be about 8 cups of liquid. If not, place the corn and fruit in a saucepan with water just to cover and simmer for about 20 minutes. Strain and add amount needed to total 8 cups. Discard the corn and fruit. Place the liquid in a heavy saucepan, reserving 1 cup of the liquid.
Add the dried prunes, cherries and apricots to the 7 cups of liquid.
In a small bowl, combine the reserved 1 cup of liquid and the sweet potato flour or cornstarch. Mix thoroughly with a fork until dissolved. Pour this mixture back into the saucepan with the liquid and dried fruits. Bring to a boil over medium heat, whisking until the mixture is thick, about 25 minutes.
Remove from the heat and pour the pudding into a deep 2 quart serving dish or individual ramekins. Let cool. To serve, dust the top with ground cinnamon.
Serve the pudding with crema.
c.1997, M.S. Milliken & S. Feniger, all rights reserved