Heat oven to 350º. Grease bottom only of 1 loaf pan, 9 × 5 × 3 inches. Mix sugar and butter in large bowl. Stir in eggs. Add bananas, buttermilk and vanilla until smooth. Stir in flour, baking powder, salt and baking soda just until flour is moistened. Stir in pecans. Pour into pan.Bake about 1 hour 15 minutes or until toothpick inserted in center comes out clean. Cool 5 minutes. Loosen sides of loaves from pans; remove from pan. Cool completely on wire rack before slicing. Store tightly wrapped in refrigerator up to 1 week.