Preheat the oven to 350°F. Line a baking sheet with parchment paper or a baking mat, set aside.
In the bowl of a stand mixer cream the butter, brown sugar, and granulated sugar, about 2-3 minutes.
Add the egg, vanilla extract, and light corn syrup and mix to combine.
Add the flour, 1 ¼ cups graham cracker crumbs, cornstarch, baking soda, baking powder, and salt and mix until combined.
Using a ¼ cup, portion the dough into round balls. Roll the balls in the 2/3 cup of graham cracker crumbs. Place 6 balls of dough on a baking sheet. Gently press on the tops of each ball with the palm of your hand to flatten each ball into a thick disk.
Bake for 10-12 minutes or until edges and tops are just set. (I baked mine for 10 minutes). You don’t want to overbake cookies.
Remove from the oven and let cool on pan for 5 minutes before transferring to a wire rack to cool completely.