Preheat oven to 350 degrees Fahrenheit with the rack in the middle of the oven.
Grease a 12-cup muffin pan with cupcake liners or oil spray.
In a medium bowl, mash the bananas. Add the oil, honey, eggs, and vanilla and mix until well combined.
In a large bowl, mix the 1 ¾ cup flour, salt, baking soda, and cinnamon until well combined.
In a small bowl, add the blueberries and 1 tbsp flour. Toss the blueberries until they are coated with flour.
Add wet ingredients to the large bowl with the dry ingredients and mix until just combined.
Add the flour-coated blueberries and chopped nuts if using. Mix until just combined.
Put the batter evenly into the lined/greased muffin pan. Place in the oven and bake for 18 to 22 minutes. Check the muffins by inserting a toothpick through the center of the muffins. The toothpick should come out clean.
Let the muffins cool in the muffin pan on a wire rack for 5 minutes. Remove the muffins from the pan and let cool for at least 20 minutes before serving.