Melt butter in large, microwave-safe bowl and allow to cool completely.
1 cup unsalted butter
Stir in brown sugar and maple syrup until completely combined.
1 ½ cup brown sugar, ⅓ cup maple syrup
Stir in vanilla extract and maple extract.
1 teaspoon vanilla extract, ¾ teaspoon maple extract
Add egg and stir until well-combined.
1 large egg
In separate, medium-sized bowl, combine flour, cornstarch, baking powder, baking soda and salt.
3 cups all-purpose flour, 2 teaspoon cornstarch, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt
Gradually (about ¼ of the mixture at a time), add the flour mix to the butter mixture and stir until completely combined.
Chill in refrigerator for at least two hours (may chill longer, up to 5 days).
Once dough is about 30 minutes from being ready, preheat oven to 375F and line a baking sheet with parchment paper.
Once dough has chilled, scoop into round 1 ½" scoops. Roll in or sprinkle lightly with granulated sugar and bake for 10-12 minutes.
Granulated sugar for rolling or sprinkling
Allow cookies to cool completely on cookie sheet. Do not put dough for following batches on hot cookie sheets, cookie sheets should always be room temperature or colder.
Video
Notes
I rolled these cookies in coarse sugar and sprinkled with golden sugar sprinkles and stars for decoration while they were cooling.