Preheat oven to 300°. Spray and flour your loaf pan. Using a mixer cream together butter, sugar, eggs, bananas, and vanilla. Add in flour, baking soda, and baking powder. After the batter is mixed, add nuts. Pour in a pan (I sprinkle a little sugar on top of the batter) and bake for one hour. After an hour check to make sure it is done by putting a toothpick in the center. If it comes out clean then it is done. If the top seems to be getting too brown, I put a piece of foil on top for the rest of the baking time. Let cool and enjoy!