Add eggs and mix well.
Sift together: flour, soda, and salt. Combine the flour mixture with the butter mixture.
Add the bananas, sour cream, and vanilla and mix well. Add the chopped nuts.
Pour the batter into a greased 9x5x3 loaf pan or several smaller loaf pans (or muffin tins).
Bake in 350 degree oven for 1 hour for 1 loaf, or around 20 minutes for muffins or small loaves.