Preheat oven to 350°F (175°C) and grease a 9-inch loaf pan with cooking spray or parchment paper.
In a large bowl, whisk together flour, sugar, brown sugar, baking soda, and salt.
In a separate bowl, mix mashed bananas, Greek yogurt, eggs, vegetable oil, and vanilla extract until smooth.
Gently fold the wet ingredients into the dry ingredients until just combined. Do not overmix.
If using, fold in chopped walnuts, pecans, or chocolate chips for extra flavor.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 50-60 minutes, or until a toothpick inserted in the center comes out clean.
Let cool in the pan before transferring to a wire rack to cool completely.
Slice and enjoy!