Preheat oven to 350 degrees F. Grease 9x13" pan with cooking spray or butter.
In a large bowl, combine oats, flour, cinnamon, baking soda, salt, and flaxseed meal.
In a medium bowl, combine banana, coconut oil, milk, honey, eggs, and vanilla, and whisk together well.
Add wet ingredients to dry ingredients and stir together with spatula until combined.
Fold in chocolate.
Pour batter into prepared pan.
Bake in preheated oven for 35-38 minutes, until edges are golden and a tester/toothpick comes out clean. I just like to tap the middle of it and if it still seems dough-y, I bake for a couple more minutes.
Let cool.
Cut into squares and enjoy!
Cover and refrigerate.