Prepare the dry ingredients by sifting together all-purpose flour, cornstarch, baking soda, baking powder, and salt. Set aside.

Cream softened butter, dark brown sugar, and granulated sugar until light and fluffy, about 3-5 minutes.

Add the egg, egg yolk, and vanilla extract, beating until fully combined.

Slowly incorporate dry ingredients into the wet mixture until combined. Do not overmix.

Shape the dough into 1-inch balls and make indentations for filling. Chill for 30 minutes.

To make the filling, combine butter, dark brown sugar, and maple syrup in a saucepan over medium heat. Stir until melted.

Add chopped pecans, heavy cream, cinnamon, cloves, and nutmeg to the mixture. Cook for 2-3 minutes until thickened.

Preheat the oven to 350°F (175°C). Fill each dough indentation with the pecan filling and bake for 10-12 minutes.

Cool the cookies on the baking sheet for 5 minutes before transferring to a wire rack. Drizzle with remaining filling and sprinkle with sea salt.