Pre-heat oven to 350 degrees.

In a bowl, mix together flour, baking soda, cinnamon, and salt.

In another large bowl, mix together brown sugar, white sugar, oil, and water. Add the mashed banana and vanilla extract.

Mix the dry ingredients into the wet ingredients above gradually while mixing.

Stir in the oats (optional - if you like raisins, you can stir a handful in at the same time).

Let the final mixture stand for a brief time if the consistency is too loose.

Layer a cookie pan with foil. Drop the cookie dough onto the pan by the tablespoon. No need to make sure the dough is round, you can just drop it on.

Cook for 13-15 minutes. The bottom of the cookie should be brown.

Remove the cookies from the oven, and let them stand for a few minutes before taking them off, and then let them cool completely on a rack.