There are plenty of ways to freestyle with this bread. You can use American persimmons, or Japanese hachiya persimmons, both of which need to be gooshy before you can really eat them -- otherwise they are astringent. As for the fruits and nuts, I prefer either black walnuts or hickory nuts, but regular walnuts or pecans are also nice. I happen to have lots of dried lingonberries lying around, so I used them. They can be tough to find, though, so "craisins," the dried cranberries you can buy, will get you close. But really any dried fruit works. If they are large, like apricots or dates, chop them small.
Prep the pans. Butter two 9-inch loaf pans and then dust them with a little flour, shaking out any excess. Preheat the oven to 350°F.
Mix the dry ingredients. Whisk together the flours, salt, baking soda, nutmeg and sugar.
Mix the wet ingredients. Whisk together the cooled, melted butter and duck fat, the persimmon puree and the eggs.
Make the batter. Add the wet ingredients to the dry and mix together. As you are doing this, add the nuts and fruit. Pour the batter into the loaf pans and bake for about 1 hour, until a toothpick comes out of the bread clean. Let rest a few minutes, then turn out gently onto cooling racks.
This bread keeps wonderfully. At least a week at room temperature, wrapped up, and basically forever in the freezer.