"This is my grandmother's recipe that she made each Thanksgiving when I was growing up. She was a native Hoosier and resided in Orleans, IN for many years. Although not a huge fan of cooking, this is one recipe she made very well and it is always one that makes me remember her fondly. Serve chilled and top with whipped cream."
Combine buttermilk and baking soda together in a bowl.
Combine flour, baking powder, cinnamon, and salt in a separate bowl.
Mix persimmon pulp and sugar together in a large bowl. Beat in eggs. Add buttermilk mixture alternately with flour mixture, stirring until combined. Stir in heavy cream and melted butter. Pour batter into a 9x13-inch baking pan.
Bake in the preheated oven until edges pull away from the sides of the pan and cracks begin to appear in the center, 25 to 30 minutes. Chill until serving.