Preheat the oven to 350 degrees F (175 degrees C). Generously grease a 10 inch fluted tube pan (such as Bundt).
Whisk flour, cinnamon, baking powder, baking soda, ginger, salt, nutmeg, cloves, and allspice together in a medium bowl.
Whisk bananas, pumpkin, yogurt, eggs, maple syrup, and vanilla extract together in a large bowl until well combined. Add flour mixture in 2 batches, mixing briefly after each addition: fold in chocolate chips and walnuts. Pour batter into the prepared pan.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 50 to 55 minutes. Cool on a wire rack for 10 minutes. Tap the pan firmly a few times, then shake it gently to loosen the cake. Place a wire rack over the pan and invert to release cake onto the rack to cool completely.
Banana-Pumpkin Bundt Cake · Dinner Match Lab | Dinner Match Lab