Preheat oven to 325 degrees. Coat a 8½-loaf pan with cooking spray. Set aside.
Using an electric mixer or fork, in a large bowl, mash the bananas.
Add sugar and mix until smooth.
Stir in egg, canola oil and applesauce.
Add flour, vanilla, baking soda, salt, ¼ cup Grape-Nuts and mix until well blended. Pour batter into prepared pan.
In a small bowl, mix together the topping ingredients and sprinkle on top of batter. Bake for 60 to 70 minutes until a toothpick inserted comes out clean. Cool for 5 minutes and remove from pan.