In a large bowl, beat the egg until lightly colored. Add sour cream; honey and vanilla. Beat again. Mash bananas with potato masher or a fork; add to the egg mixture. Add nuts. Sift together remaining dry ingredients. Combine with banana mixture and blend lightly.
Pour batter into a greased 8 1/2x4 1/2" loaf pan. Bake at 350'F. about 1 hour,