- Preheat oven to 350F (175C). Grease and flour a 9x5 inch loaf pan. 
- In a medium bowl, whisk together flour, baking soda, cinnamon, and salt. 
- In a separate large bowl, cream together the softened butter and sugar until light and fluffy. 
- Beat in the eggs one at a time, then stir in the vanilla extract. 
- In a small bowl, mash bananas. 
- Add the Greek yogurt to the butter mixture and mix well. Then, add the mashed bananas and combine. 
- Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix. 
- Fold in the chopped nuts, if using. 
- Pour batter into the prepared loaf pan and spread evenly. 
- Bake for 50-60 minutes, or until a wooden skewer inserted into the center comes out clean. 
- Let the bread cool in the pan for 10 minutes before transferring it to a wire rack to cool completely. 
- Slice and serve. 
- Optional Tips: 
- For a moister bread, add an extra cup of mashed banana. 
- Substitute applesauce for half the butter to reduce fat content. 
- Add chocolate chips for a richer flavor. 
- To prevent the top from browning too quickly, tent the loaf pan with foil during the last 15 minutes of baking.