Preheat the oven to 350° F. Spray a 8x8 square baking pan with non-stick spray or line with parchment paper, and set aside.
In a large bowl, whisk together the oats, cocoa powder, baking powder, and salt.
Pour in the milk, maple syrup, eggs, oil, and vanilla. Stir until everything is combined. Fold in the chocolate chips.
Pour the oat mixture into the baking pan, topping with extra chocolate chips, and bake for 30-40 minutes (or until the center is set). Allow the oats to cool in the pan for a few minutes before serving.
