Prepare the Pan: Preheat your oven to 350°F (175°C). Grease and lightly flour a 9x5-inch loaf pan.
Toast the Walnuts: In a dry skillet over medium heat, toast the walnuts, stirring constantly until fragrant. Remove from heat, coarsely chop, and set aside to cool.
Make the Batter: In a large mixing bowl, cream together the softened butter and sugar until light and fluffy. Mash the bananas with a fork until slightly chunky (like applesauce) and stir them into the butter mixture along with the beaten eggs until well combined.
Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet mixture, stirring just until incorporated.
Add Flavorings: Stir in the vanilla extract, chopped walnuts, and raisins.
Bake: Pour the batter into the prepared loaf pan and smooth the top. Bake for 55–60 minutes, or until a toothpick inserted in the center comes out clean.
Cool and Serve: Allow the bread to rest in the pan for 10 minutes, then transfer it to a wire rack to cool completely before slicing.