Cut about ⅛ of a kabocha into 1cm sized cubes. Cut the remaining ⅛ into larger chunks. The size doesn’t matter as it will be used to make the puree.
Prepare the kabocha puree by steaming about ⅛ of a kabocha cut into chunks. You can do this over the stove or in the microwave like I did in the pumpkin bagel recipe. While it’s still hot, use a potato masher, fork, or food processor to mash the kabocha into a puree. Depending on the condition of your kabocha, you may need to add moisture, so feel free to use water or milk to help with the consistency. We don’t want it too wet, though, so mind the moisture. It should be roughly the same consistency as mashed potatoes. This will make about 120g of kabocha puree which will be used as part of the liquids for the dough. Combine the flour, sugar, salt, and baking powder in a bowl.
Cut the cold butter into cubes, and add it to the flour mixture. With cold hands, crumble the butter with the flour until it is evenly distributed. You should be able to squeeze a small amount in your fist and have it maintain its shape. If you have a food processor, you can use it instead and it will make this process so much easier. Simply add the flour mixture and butter into the bowl of the food processor and let it go until just combined then return to the flour bowl. Be mindful, though, that the quickness of this method and the machine can generate heat which can melt the butter a bit, so don’t let it run for too long or let it process in pulses.
Create a well in the middle of the flour mixture and pour in the heavy cream and kabocha puree. Gently fold the dough until just incorporated.
Add the cubed kabocha and gently fold in until evenly distributed. Be careful not to overwork the dough.
Transfer the dough onto a floured surface to work it together. Shape the dough into a circle about 3cm thick.
Cut the dough into 8 pieces that are all roughly the same size and place the pieces onto a baking tray lined with parchment paper. This is optional, but you can brush the tops with an egg wash made from an egg yolk and about 4 teaspoons of milk. This will help the scones have a golden brown shine.
Bake at 425°F/220°C for 10-12 minutes. Let the scones cool for about 5-10 minutes before you handle them, and the pumpkin scones are done! 完成です!