Set oven to 350 degrees F. Line the bottom of a loaf pan with parchment paper.
Sift together the flour, baking soda, cinnamon and salt. Beat sugar and eggs with a whisk until light and fluffy, about 10 minutes. Drizzle in oil. Add mashed bananas, creme fraiche, and vanilla. Fold in dry ingredients and nuts. Pour into a lined loaf pan and bake for about 45 minutes to 1 hour.