Heat oven to 350°F . Grease bottoms only of 2 (8x4-inch)loaf pans or 1 (9x5-inch)loaf pan.

In large bowl, mix sugar and butter. Add eggs,bananas,buttermilk and vanilla ; beat with electric mixer on medium speed until smooth.Stir in flour,baking soda,salt and nuts just until moistened. Pour batter into pans.

Bake 8-inch loaves 1hour,9-inch loaf 1 1/4 hours, or until toothpick inserted in center comes out clean. Cool 10 minutes. Loosen sides of loaves from pans; remove from pan to cooling rack. Cool about 1 hour before slicing.

High Altitude (3500-6500ft): Increase flour to 2 3/4 cups. In step 1,heat oven to 375°F. In step2,add 1/4 cup water with buttermilk. Bake 8-inch loaves about 1hour 5minutes,9-inch loaf about 1hour 30 minutes.