Preheat oven to 350 degrees F.
Line a baking sheet with parchment paper.
In a mixing bowl, add the mashed bananas, egg, syrup, vanilla, and oil. Whisk well to combine.
Add the flour, oats, pecans, and chia seeds. Stir well to incorporate all the ingredients.
Place the bowl in the refrigerator for 10 minutes. This helps the cookie batter setup.
Drop tablespoons of the batter onto the prepared baking sheet. If you prefer a flatter cookie, use a fork to flatten the cookies slightly. These cookies do not spread out during the baking process.
Bake cookies for 15 minutes or until golden brown.