Preheat your oven to 350°F (175°C) and prepare an 8-inch square baking pan with parchment paper and light greasing.

In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, brown sugar, baking soda, baking powder, salt, and ground cinnamon.

In a separate bowl, whisk together the melted unsalted butter, pure maple syrup, milk, large egg, and vanilla extract until smooth.

Gently fold the wet mixture into the dry ingredients using a spatula, being careful not to overmix.

Pour the batter into your prepared baking pan, spreading it evenly and ensuring the top is smooth.

Place the pan in the preheated oven and bake for 20-25 minutes until a toothpick comes out clean.

Allow the bars to cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely.