Preheat the oven to 350°F (175°C) and line baking sheets with parchment paper.

Cream together 1 cup of softened unsalted butter and 1 cup of packed brown sugar until light and fluffy. Add in 1/4 cup of pure maple syrup, 1 large egg, and 1 teaspoon of vanilla extract, mixing until well blended.

Whisk together 2 1/2 cups of all-purpose flour, 1 teaspoon of baking soda, 1/2 teaspoon of salt, and 1/2 teaspoon of ground cinnamon. Gradually incorporate into the wet ingredients until just combined.

Scoop dough into 1 1/2-inch balls and place them on prepared baking sheets, flattening gently.

Bake for 8 to 10 minutes until edges are golden and centers are soft. Allow cooling on the sheets for a few minutes before transferring to a wire rack.

Prepare the maple glaze by whisking together 1 cup of powdered sugar, 2 tablespoons of pure maple syrup, and 1-2 tablespoons of milk to achieve a smooth consistency.

Once cookies are cool, drizzle the glaze over each cookie and sprinkle with cinnamon if desired. Let the glaze set before serving.