Preheat oven to 350°F. Line two baking sheets with parchment paper.
In a bowl, whisk flour, cornstarch, baking soda, salt, cinnamon, and cream of tartar. Set aside.
Using an electric mixer, beat butter, brown sugar, and granulated sugar until light and fluffy (about 1-2 minutes).
Add maple syrup, egg, and maple extract, mixing until incorporated.
Gradually add dry ingredients and mix until just combined.
In a shallow bowl, mix granulated sugar and cinnamon for rolling.
Using a 3-tablespoon scoop, form dough balls and roll in cinnamon sugar. Place on baking sheets about 2 inches apart.
Bake for 11-13 minutes until edges are set but centers remain soft. Cookies will firm as they cool.
Cool on baking sheet for 5 minutes, then transfer to wire racks.