Preheat the oven to 375°F. Line 12 muffins tins with paper liners or oil.
In a small bowl, blend the 3 tbsp of white sugar and 1 tsp of cinnamon. Set aside.
In a medium-sized bowl, sift the flour, granulated sugar, cinnamon, salt, baking powder and baking soda together. Whisk until well blended.
In a large bowl with a fork or in a bowl of stand mixer with paddle attachment, blend the bananas, plant milk, oil, brown sugar, vinegar and vanilla extract. Mix until very well blended and no big chunks of banana pieces remain.
Add the dry mixture to the banana mixture and mix together just until blended but do not over-mix. Using a large ice cream scoop or a 1/3 cup measuring cup, scoop the batter into the muffin tins. Fill each one about 2/3 to 3/4 full. Sprinkle each muffin with the cinnamon sugar.
Bake for 18-22 minutes or until a toothpick inserted in the middle of a muffin comes out clean. Let cool for 10 minutes before eating. Store in an air-tight container.