Preheat the oven to 375F. Line a 12 cup muffin tin.
Make the faux buttermilk by mixing soy milk and vinegar in a 1 or 2 cup measuring cup
In a medium-large glass mixing bowl, combine the dry ingredients: flour, oats, white sugar, brown sugar, baking powder, baking soda and salt. Stir to mix well then set aside.
Add buttermilk to the dry ingredients and mix well. Next add in the oil, vanilla and mashed bananas. Stir to combine. Do not over-mix. If you would like to add chocolate chips, gently mix them in right now. If only adding them to half the batter, sprinkle them in by hand into the individual muffin cups.
Spoon batter into prepared muffin tin, filling 3/4 way full. Bake for 16-20 minutes, until tops spring back when tapped and internal temperature is about 200F. Let sit for a minute then carefully remove hot muffins from pan to a cooling rack.