Preheat your oven to 350°F (175°C) and prepare an 8×8-inch baking pan by lining it with parchment paper or greasing it with butter.

In a large mixing bowl, combine melted butter, brown sugar, and granulated sugar. Whisk until smooth and creamy.

Add eggs, maple syrup, milk, and vanilla extract. Mix until well combined and smooth.

In a separate bowl, whisk together flour, baking powder, baking soda, salt, and cinnamon if using.

Gently fold the dry mixture into the wet ingredients until no flour streaks remain.

Pour the batter into the prepared baking pan and spread it evenly across the surface.

Bake for 22–25 minutes until a toothpick comes out clean. The edges should be lightly golden.

Allow the bars to cool completely in the pan for about 20-30 minutes.

Prepare the maple glaze by whisking together powdered sugar, maple syrup, milk or cream, and a pinch of salt.

Once the bars are cooled, spread the glaze over the top and let it set for 10 minutes before slicing.