Preheat your oven to 350°F (175°C). Grease a 9x5-inch loaf pan and, if you want an easier cleanup, line it with parchment paper.
In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon.
In a large mixing bowl, whisk the brown sugar, oil, eggs, Greek yogurt, vanilla, and mashed bananas until everything is smooth and well combined.
Gently fold the dry ingredients into the wet mixture just until you don’t see any more streaks of flour. A few lumps are totally fine — overmixing will make your bread dense.
Pour the batter into your prepared loaf pan, smooth the top, and pop it into the oven. Bake for 50–60 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs.
Let the bread cool in the pan for about 10 minutes before transferring it to a wire rack. Let it cool mostly before adding the glaze — warm glaze on hot bread will just run right off.