Heat oven to 400 Deg. Set out a baking sheet with parchment paper.
Mix flour, brown sugar, baking powder, cinnamon, nutmeg, cardamom and salt in a large bowl
In a separate bowl mix oil, egg, vanilla and cream. Add this to flour mix and mix until starting to combine. Add in the chopped persimmon and chocolate chunks. Mix until it comes together. You might have to use your hands for this.
Scoop out dough onto a piece of parchment paper that has been lightly floured. Pat dough to a 7-8 inch round thick disc. Transfer on the paper to a baking sheet and freeze for 20 minutes.
Cut disc into 8 wedges and place the wedges a few inches apart on the parchment lined baking sheet. Press a few persimmon pieces and dark chocolate chunks into the tops of the scones. Chill for another 20 minutes.
Chilling or freezing the dough between shaping into a disc then again after cutting into wedges makes it easier to handle them before being baked and helps keep their shape when baking.
Make egg wash by whisking together the egg, cream and water then brush tops of the scones with it. Generously sprinkle scones with coarse sugar.
Bake scones for 20 minutes or until set and starting to turn golden. Transfer to a cooling rack to cool slightly then serve. Best eaten same day as baked. Can be frozen and reheated slightly after thawing if eating at a later date.