Preheat oven to 400°F. Grease loaf pan (or pans) and set aside.
In a 2 cup measuring cup, mash the banana until well pureed. Pour into mixing bowl. Add the soy milk, oil, sugar, vinegar and vanilla to the mashed bananas in the mixing bowl. Stir well.
Add the dry ingredients (flour, salt, baking powder, cinnamon) to the wet ingredients. Mix well until batter comes together. Try not to over-mix batter.
Pour into prepared loaf pan(s), only fill to about halfway, otherwise the top will over-brown and the inside won't be cooked.
Sprinkle top with cinnamon, take a knife or chopstick and swirl it around to create a swirl effect. Sprinkle desired amount of brown sugar on top (2-3 tablespoons approximately.)
Bake in preheated oven for 30-40 minutes depending on pan sizes and depths, until internal temperature reaches about 200°-205°F or toothpick comes out clean. If using food thermometer for measuring, make sure you poke and check the top as the batter on top will be slowest to cook through.
Allow to cool before digging in; banana bread tastes better when cooled down!