This cake is sure to become a holiday favorite — not only does it look and taste great, but it's a snap to make. Dense and moist, it holds extremely well, and the ginger flavor intensifies as the cake mellows. Try it for breakfast or brunch!
Position a rack in the middle of the oven and heat to 350 degrees F. Butter a 9-inch cake pan and set aside.
Place 1 stick (1/2 cup) of soft butter in the bowl of an electric mixer and add the 3/4 cup of brown sugar. Beat until the mixture is smooth, then beat in the eggs, one at a time. Add the ginger root, 1/3 cup of the crystallized ginger, and 1/4 cup of heavy cream.
Place the flour, baking powder, ground ginger and salt in a medium bowl and whisk to combine.
With the mixer set on low speed, gradually add the dry mixture, mixing just until combined. Transfer the batter to the prepared pan. Arrange the persimmon slices in slightly overlapping concentric circles atop the batter. Press the fruit lightly into the batter.
Melt the remaining tablespoon of butter. Sprinkle the remaining 3 tablespoons of brown sugar over the fruit and drizzle with the melted butter. Bake until the cake is set and a toothpick inserted into the center comes out clean, 40 to 45 minutes. Turn the oven off and broil the cake until the sugar melts and begins to glaze the fruit, 3 to 5 minutes.
Transfer the cake to a wire rack and let cool for 10 minutes in the pan. Run a knife around the edge of the cake, invert the cake onto a plate, and then invert again onto the wire rack to finish cooling.
Before serving, whip the remaining 3/4 cup heavy cream with the confectioner's sugar. Serve slices of the cake with a dollop of whipped cream, and garnish with a sprinkling of the remaining minced crystallized ginger.
Cover leftover cake tightly with plastic wrap and store at room temperature for up to 3 days.