To prepare Streusel Topping: In a small bowl, combine sugar, all-purpose flour, whole wheat pastry flour, wheat germ, and pumpkin pie spice. Stir in butter.
To prepare Persimmon Cake: Preheat oven to 350°F. Lightly coat a 13x9x2-inch baking pan with nonstick cooking spray; set pan aside. In a medium bowl, combine all-purpose flour, whole-wheat pastry flour, wheat germ, baking powder, pumpkin pie spice or apple pie spice, and salt; set aside.
In a large bowl, combine sugar and oil; beat with an electric mixer on medium speed until combined. Add egg and vanilla to sugar mixture; beat on medium speed about 1 minute or until creamy, scraping side of bowl occasionally. Stir in milk. Using a wooden spoon, stir flour mixture into egg mixture. Pour batter into the prepared pan. Arrange chopped persimmons or plums over batter. Sprinkle Streusel Topping over fruit.
Bake for 40 to 45 minutes or until a toothpick inserted near the center comes out clean. Serve warm or cool, cut into squares, with dessert topping, if desired.
Tip: Leaving the peel on the persimmons or plums adds fiber to this luscious coffee cake.