Set the oven to 400 degrees. Spread the chestnuts and apples on a baking sheet and roast for ten minutes. Set aside. Melt butter in a stockpot over medium heat. Add the onion and garlic. Cook for five minutes, stirring occasionally.
Add the persimmons, chestnuts, sweet potatoes and apples and cook for ten minutes more, still on medium heat. Add the vegetable stock. Increase the heat and when the liquid begins to boil, reduce it to a simmer. Add the allspice, cinnamon, clove, and a pinch each of salt and pepper into persimmon-stock mixture. Heat slowly over medium heat, stirring until it reaches a simmer, but not a boil. Let simmer for 30 minutes or until the potato is tender. Remove from the stove and puree until smooth. Strain through a chinois. Season the soup with salt, pepper and sugar. Serve warm.