Preheat oven to 350 F. Rub a loaf pan with oil and line with a rectangle of parchment.
Mix together the soy milk and vinegar; set aside for about 2 minutes.Stir together flour, baking soda, salt and cinnamon.Beat together the oil, brown sugar and granulated sugar, then beat in the bananas – you can mash them ahead of time or let the paddle attachment of the stand mixer do the work for you. I just chunked the bananas in with the oil & sugar and beat them that way. Continue beating on high until very light. Reduce speed to low and add milk/vinegar mixture. By hand, stir the flour mixture into the banana mixture, being careful not to overbeat. I like stirring flour mixture in with a heavy duty scraper.
Sprinkle some nuts on top if using.
Bake for 1 hour or until a toothpick inserted in center comes out clean.
Let cool on a rack for about 15 minutes then flip from pan. Makes 1 awesome loaf.