Preheat oven to 375 degrees.
In a bowl, mix together dry ingredients. Oats, brown sugar, baking soda, cinnamon, and chocolate chips.
Fold frozen berries into dry mix.
Dump dry mixture into a greased, 9" x 13" pan
In a separate bowl, whisk together melted butter, almond milk, egg, and vanilla extract.
Pour the mixture over the oatmeal mixture making sure to evenly distribute it. You can shake the pan a little to make sure it is getting distributed everywhere.
Slice your banana into 1/4 inch slices and spread them out over the oatmeal.
Bake for 30-35 minutes or until it looks fully cooked.
Sprinkle with additional brown sugar and serve warm.