Preheat oven to 350 degrees. Line a 15x10 rimmed baking sheet with parchment paper.
In a small bowl, combine the flour, baking soda, cinnamon and salt.
In a large mixing bowl, whisk together the butter and light brown sugar. Add the buttermilk and eggs. Mix well to combine.
Add the dry ingredients and mix well. Add the mashed bananas and chocolate chips. Mix until combined.
Spread the batter evenly in the prepared baking sheet. Bake for 18 - 20 minutes until slightly browned and cooked through.
Allow to cool and cut into squares. Alternatively, use a cookie cutter to cut into shapes.