preheat oven to 350 degrees, lightly grease 2 baking sheets.

In a mixing bowl mash the banana well. You can use a fork for this but your hands work well too. Add the oil sugar and vanilla, mix with a strong fork. Add the flour, baking soda and cinnmon and mix until the dry ingredients are just moistened. Add the oatmeal walnuts and chocolate chips and mix well. Isa recommends using your hands for mixing in the oatmeal to ensure that the oats get moist. If the dough is quite slippery you may wish to add a few tablespoons of extra flour. This just depends on how big your banana is.

Clean your hands and roll the dough into balls slightly smaller than a golf ball, flatten it a bit in your hands and place each ball about 2 inches apart on the cookie sheet. Bake for 10-12 minutes until lightly browned. Let the cookies cool on the cookie sheet for 2 mins then transfer them to a cooling rack.