Adjust the oven rack to the lower third position and preheat the oven to 350°F. Line and grease a 9×5-inch loaf pan with nonstick spray. Set aside.
Whisk the flour, baking soda, salt, and cinnamon together in a large bowl.
Using a stand mixer fitted with a paddle attachment beat the butter and brown sugar together on high speed until smooth and creamy, about 2 minutes.
On medium speed, add the eggs one at a time, beating well after each addition.
Beat in the yogurt, mashed bananas, and vanilla extract on medium speed until combined.
With the mixer running on low speed, slowly beat the dry ingredients into the wet ingredients until combined. Do not overmix. Fold in the nuts, if using.
Pour the batter into the prepared loaf pan and bake for 60-65 minutes. Loosely cover the bread with aluminum foil after 30 minutes to help prevent the top and sides from getting too brown.
The bread is done when a toothpick inserted in the middle comes out clean. Remove from the oven and allow the bread to cool completely in the pan set on a wire rack.