Preheat the oven to 425°F (218°C).
Put 4 muffin papers in your muffin tin. Spray them with cooking spray.
In a medium-sized bowl, stir the Kodiak Cakes mix, milk powder, and cinnamon together. In a small bowl, mix the mashed banana, oil, and whole milk. Pour the wet ingredients into the dry ingredients and gently stir.
Divide the batter evenly between the four prepared muffin liners. Top each muffin with chocolate chips (if using).
Bake muffins for 10-12 minutes on a rack about one-third of the way down in the oven.
After baking, check the Kodiak banana muffins for doneness by inserting a toothpick in one of them. The toothpick should come out clean or with small crumbs.
Cool the muffins on a baking rack for 30-60 minutes before putting in the fridge. Enjoy these Kodiak Cakes banana muffins fully chilled for the best texture.