Preheat oven to 350°F. Spray a 9x5-inch loaf pan with nonstick spray and cut a piece of parchment the length of the pan and 4 inches wider than the pan's width (it should stick up 2 inches over each side of the pan, when placed inside the pan). Place the paper in the pan and spray it. Once the bread is baked, the paper will be used like a sling to lift the bread out of the pan.
Place the bananas in a large bowl and mash with a fork or potato masher. Add the oil, eggs, brown sugar, and vanilla. Mix well to blend.
4 bananas, ½ cup canola oil, 3 large eggs, 1½ cups dark brown sugar, 1 teaspoon pure vanilla extract
In another small bowl, sift together the flour, cinnamon, and salt. Add the flour mixture to the banana mixture. Mix just until flour is incorporated.
1½ cups self-rising flour, 1 teaspoon ground cinnamon, ½ teaspoon kosher salt
Pour the batter into the prepared loaf pan. Bake for 1 hour, or until a toothpick comes out clean when inserted in the middle of the bread.
Place the pan on a cooling rack and let the bread rest for 5 minutes before removing it from the pan. Let cool completely.