PREHEAT OVEN: 350º with rack in middle.
1. Butter and flour a 9 by 5 inch loaf pan, knocking out
2. Whisk together flour, baking powder, baking soda,
and salt in a bowl. Mash bananas with a fork in
another bowl, then whisk in sugar, oil, eggs and
vanilla. Whisk in flour mixture until just combined.
3. Pour batter into pan, smoothing top.
4. Bake until wooden pick inserted in center comes out
clean, about 1-1/4 hours.
Turn bread out onto a rack and cool completely.