1. Preheat oven to 350 degrees F.
2. Mash bananas into a smooth paste and set aside.
3. Combine rest of the ingredients, except walnuts, and mix into a thick and smooth batter.
4. Add mashed bananas and walnuts, reserving some. Mix well.
5. Pour the batter into a buttered baking pan and sprinkle the reserved walnuts.
6. Bake for 90 minutes, or until a toothpick inserted comes out clean.
7. Remove and cool.
8. Transfer the cake in a tray and cut into serving pieces.

Calories: 450 Kcal