Preheat the oven to 350F/177C. Line the bottom and sides of a brownie pan; mine is about 13x7-inches (33x17-cm) in size.

In a large mixing bowl, beat together the softened butter, sugar and vanilla for 2 to 3 minutes, until the mixture is creamy. Add the eggs and mix again for 1 minute. Peel the bananas and crush them using a large fork or food processor. Add the banana puree to the batter and fold it in.

In a separate bowl, combine the dry ingredients: flour, baking powder, baking soda, cinnamon, nutmeg and salt. Sift the dry ingredients into the batter and fold gently just until the flour is incorporated, then fold in the pecans. Transfer the batter into the prepared pan and spread it evenly to the edges using an off-set spatula.

Bake the banana nut bars for 30 to 35 minutes, until golden brown on top and a toothpick inserted into the center comes out clean. Remove the bread from the oven and cool completely on a wire rack.

Once the bread is cooled, prepare the cream cheese frosting. In a large mixing bowl, whisk the cream cheese for a few minutes, until it's creamy and smooth. Add the maple or vanilla extract, confectioner's sugar and a pinch of salt. Mix again for a few minutes until the frosting is smooth and creamy. To make the frosting thinner, just add a few tablespoons of heavy cream.

Spread the cream cheese frosting over the banana nut bread with an off-set spatula. For the optional topping, simply combine the melted butter, sugar, nuts and spices in a small bowl, then sprinkle over the frosting.