Toast Pecans: In a medium skillet, melt a tablespoon of unsalted butter over medium heat. Add chopped pecans and cook for 4-5 minutes, stirring until fragrant and lightly golden. Remove from heat and set aside.

Prepare Flour Mixture: In a mixing bowl, whisk together all-purpose flour, cornstarch, salt, ground cinnamon, and baking soda. Set aside.

Brown Butter: In a saucepan over medium-low heat, melt unsalted butter until foamy and amber-colored, about 5-7 minutes. Allow to cool slightly.

Combine Wet Ingredients: Whisk together browned butter, dark brown sugar, and granulated sugar until well blended. Mix in vanilla extract, eggs, and egg yolk until just combined.

Incorporate Dry Mixture: Gradually fold the flour mixture into the wet ingredients until just combined. Stir in toasted pecans.

Chill Dough: Cover the bowl and refrigerate for at least 4 hours.

Preheat Oven: Preheat oven to 375°F (190°C) and line baking sheets with parchment paper.

Shape Cookies: Portion out the chilled dough into 3-tablespoon-sized balls and place on baking sheets, spaced about 3 inches apart.

Bake: Press a pecan half onto each dough ball and bake for 10-11 minutes or until edges are golden brown. Allow to cool on baking sheet for 15 minutes.

Cool and Serve: After cooling, cookies can be stored in an airtight container at room temperature.