Preheat the oven to 350°F (175°C).
In a large mixing bowl, combine rolled oats, whole wheat flour, baking soda, cinnamon, and salt.
In another bowl, mix the mashed banana or applesauce with honey and melted coconut oil.
Pour the wet ingredients into the dry ingredients and stir until combined.
Fold in dark chocolate chips or nuts if using.
Scoop tablespoon-sized amounts of dough onto a lined baking sheet.
Flatten each cookie slightly with the back of a spoon.
Bake for 12-15 minutes, or until golden brown.
Remove from the oven and let cool on the baking sheet for 5 minutes.
Transfer to a wire rack to cool completely.