This takes an old-fashioned holiday dessert and gives it a modern update, notably, healthier ingredients and a simplified method of baking. Be sure to use very ripe, very soft persimmons to make this cake. When topped with lightly sweetened whipped cream, it’s just right for the holiday table. Leftovers are excellent for breakfast with a spoonful of plain Greek yogurt.
Use your hands to peel the skin and stem off the persimmons and put the flesh into a food processor or blender. Puree the persimmons. Measure 1 cup of the persimmon puree and put into a large bowl (save any remaining persimmon for another use, such as for topping yogurt or blending into a smoothie). Add the sugar, buttermilk, butter, egg, and vanilla to the persimmon and whisk thoroughly.
Pour into the buttered pan and bake until firm to the touch (no indent when you press with a finger), and a toothpick comes out clean, 50 minutes.
Cut into wedges and serve with a whipped cream or ice cream.