Peanut Butter Banana Chocolate Chip Oatmeal Bars

and 1/2 cups (200g) old-fashioned rolled oats (not instant or quick oats)

dark brown sugar, loosely packed (or light brown sugar)

baking powder

salt

ground cinnamon

almond milk (regular or soy milk would be fine)

vanilla extract

large egg (or 1 "flax" egg - see note below for vegan option)

large very ripe bananas, mashed

creamy peanut butter

semi-sweet chocolate chips

peanut butter chips