Preheat the oven to 177 C / 350 F and line two sheet pans (33 x 46 cm / 13 x 18 inch) with parchment paper.
In a large mixing bowl, whisk the melted butter, brown sugar, and maple syrup until smooth and glossy, about 1 minute.
Whisk in the egg, vanilla extract, and maple extract if using, until the mixture looks smooth and slightly lightened.
In a second bowl, whisk together the flour, baking soda, cinnamon, and salt.
Add the dry ingredients to the wet ingredients and fold with a spatula until just combined. The dough will be soft and a little sticky, don't overmix.
Chill the dough for 20 minutes if it feels too soft to scoop, this keeps the cookies from spreading too thin.
Stir together the granulated sugar and cinnamon in a small bowl for the coating.
Scoop the dough into 2-tablespoon portions (about 28 g each), roll into balls, then roll each ball in the cinnamon sugar until fully coated.
Place the balls on the prepared pans, spacing them 5 cm / 2 inches apart. Bake one pan at a time for 10 to 11 minutes, until the edges are set and lightly golden but the centers still look slightly underbaked.
Let the cookies sit on the hot pan for 5 minutes, they'll continue to firm up as they cool. Transfer to a wire rack to cool completely.