Preheat your oven to 350°F (175°C). Grease and flour a loaf pan measuring approximately 9.25 x 5.25 x 2.75 inches. Lightly toast the walnuts in a skillet, stirring continuously. Once toasted, coarsely chop them and let cool.

In a mixing bowl, cream together the softened butter and granulated sugar until smooth and fluffy.

Mash the ripe bananas with a fork until chunky. Add them to the creamed butter and sugar along with the lightly beaten eggs. Mix until well combined.

In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.

Gradually add the dry ingredient mixture to the banana batter, stirring gently. Add the vanilla extract, then fold in the cooled chopped walnuts and raisins.

Pour the batter into the prepared loaf pan, smoothing the top. Bake in the preheated oven for 55 to 60 minutes, or until a toothpick inserted in the center comes out clean.

Allow the banana bread to rest in the pan for about 10 minutes after baking. Then, transfer it to a wire rack to cool completely before slicing and serving.