To make banana bread, combine mashed bananas and vanilla, combine the mixture with eggs, flour and spices, add melted butter, and bake the bread for 50 minutes. This recipe from About.com yields one 9-inch loaf.
Preheat the oven to 375 degrees Fahrenheit. Spread 1 cup chopped walnuts on a baking sheet, and toast them for about five minutes. Remove them from the oven, and set them aside to cool. Place 1/2 cup butter in a microwaveable bowl, and microwave it until it liquefies. This takes about one minute. Remove the butter from the microwave, and let it cool slightly.
Put 1 3/4 cup flour into a large mixing bowl. Add 1 teaspoon baking powder, 3/4 cup sugar, 1/2 teaspoon baking soda, 1/2 teaspoon salt and 1/2 teaspoon ground cinnamon. Verify that the walnuts have cooled to room temperature, and then stir them in. Mix the dry ingredients thoroughly.
Peel 3 over-ripe bananas, put them in a large mixing bowl, and mash them thoroughly. Sprinkle 1 teaspoon vanilla extract over the bananas. Crack 2 eggs into another bowl, beat them, and pour them over the bananas. Pour a little melted butter on top, and stir it in. Add more butter, and stir the bananas again. Repeat with the remaining butter.
Grease a 9-inch loaf pan with butter, and dust it with flour. Pour the banana mixture into the dry ingredients, and stir quickly for no more than 10 seconds. Pour the batter into the loaf pan, and bake it for 50 minutes. Remove the bread from the oven, give it several minutes to cool, and then invert the pan over a wire baking rack. Leave the bread on the rack until it cools.