Preheat oven to 180°C (360°F) and line a baking sheet with parchment paper.
In a large mixing bowl mash the banana and combine with egg, peanut butter, brown sugar, vanilla extract and salt. Using a hand mixer or whisk, stir the wet mixture for a couple of minutes until all is well combined.
Add to the wet mixture rolled oats, flour and baking powder. Using a spatula, stir all ingredients together.
Stir the chocolate chips into your oatmeal cookie dough.
Scoop about 1/3 cup of dough out and shape 10 cookies. Transfer your oatmeal cookies to the parchment paper covered baking sheet, spacing them apart.
Bake in hot oven for 10 to 12 minutes. Let cool over a baking rack before serving.