Preheat oven to 375°F
Line a muffin pan with paper liners or spray with cooking spray
Combine flour, baking soda, cinnamon, and salt. Set aside.
In a large bowl, beat oil, eggs, and sugar together.
Stir in the vanilla extract and the bourbon, if using.
Beat in bananas until well combined.
Fold in dry ingredients until just combined.
Pour evenly into prepared muffin pan.
Bake for 18 to 20 minutes until baked through. Tops will be browned, and a toothpick inserted into the centre of the muffin will come out clean.
Allow to cool in pan for 2 minutes before transferring to a cooling rack.
Cool completely before storing in an air-tight container.