Oven Temp: 350° bake in upper middle of oven, 55-60 minutes
Yield: 2 loaves (8.5"x3")
Mix the flour, baking powder, soda, and salt, and put aside. It's important to mix the dry ingredients separately to avoid clumps of baking soda or baking powder and the resulting bitter taste in the finished loaf.
In the large bowl of an electric mixer, cream the butter and sugar, and beat until fluffy. At low speed, add the eggs and mashed bananas. At low speed, add the buttermilk alternately with the flour mixture. After each addition, beat just until all the ingredients are fully incorporated. Add the vanilla and nuts, and mix at low speed only until all the nuts are incorporated. Don't overbeat at any time or the bread will be too dry.
Pour the batter into two greased loaf pans. Bake for 55 minutes to 1 hour until a toothpick inserted in the middle of the loaf comes out dry. Cool on a rack. These loaves keep quite well for up to 5 days at room temperature or 3 months in the freezer.