Preheat the oven to 350°F / 175°C. Grease baking sheets with butter or non-stick cooking spray, or line with baking parchment paper or silpats.
If making the persimmon pulp yourself, use 3 very ripe and soft hachiya persimmons. Cut off the tops and scoop out the soft flesh, then puree in a blender or with a hand blender. Measure out 1 cup to use for the recipe and set aside. Save the rest for another recipe.
Add the butter and sugar to a large mixing bowl and beat together with an electric mixer well. Beat in the persimmon pulp, egg and vanilla.
Sift in the flour, baking soda, baking powder, cinnamon, nutmeg and salt and stir to combine.
Drop tablespoonfuls of the cookie dough onto the baking sheets, spaced slightly apart to allow for spreading.
Bake for 15 minutes or until the edges just begin to firm up and turn golden. Allow the cookies to cool on the baking sheets for a few minutes, then transfer to a wire rack to cool completely.
For the vanilla glaze
Sift the powdered sugar into a mixing bowl, then add the other drizzle ingredients and beat well until smooth. If the glaze is too thin, add a little more sugar, or if it’s too thick, add a little more milk. Drizzle over the completely cooled cookies.
For best results, make sure the butter and egg are at room temperature before mixing them into the cookie dough.
Do not overwork the cookie dough. Overmixing the dough could cause the cookies to become too firm and tough when baked.
When making the drizzle, if the drizzle is too thin, add a little more sugar, or if it’s too thick, add a little more milk.
Before icing the cookies, the cookies need to be fully cooled. Pouring icing on a warm cookie will cause it to melt.
If you’re making your own persimmon pulp, be sure to use very ripe persimmons of the Hachiya variety.