Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking pan.
In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, salt, and cinnamon until well combined.
In another bowl, mix the milk, melted butter, eggs, vanilla extract, and maple syrup until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Pour the batter into the prepared baking pan and spread it evenly.
Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
Allow the bars to cool in the pan for about 10 minutes, then transfer them to a wire rack to cool completely.
For the glaze, whisk together the powdered sugar and remaining maple syrup in a small bowl until smooth.
Once the bars are completely cool, drizzle the maple glaze over the top. Cut into bars and serve.