Preheat the oven to 350°F. Grease the loaf pan and line with baking paper
In a mixing bowl, cream together butter and sugar.
Add eggs and mix well
Mash bananas with a potato masher or a fork until the consistency of chunky applesauce. Add the puree to the butter along with the eggs, mixing until well blended. Add vanilla.
In a separate bowl, whisk together dry ingredients. Add dry ingredients to wet ingredients mixing well.
Fold in chopped walnuts and raisins.
Pour into prepared loaf pan. Bake at 350˚F for 50-55 min. Check the batter for doneness at the 50 minute mark, by inserting a toothpick into the center. If it comes out clean, the bread is done. If not, leave for extra 5 minutes. Cool in the pan.