In a large skillet pver medium heat, sauté the chopped pecans, brown sugar and butter for about 3-4 minutes, until lightly toasted. Set aside to cool and stir in vanilla.

In a skillet over medium-high heat, bring the butter to a boil stirring frequently. Solid particles at the bottom turn golden brown. Immediately pour into a large mixing bowl and cool slightly, for about 10 minutes.

In another bowl, whisk together the flour, cornstarch, baking soda.

Whisk the sugars into the cooled browned butter. Whisk in the vanilla, eggs, egg yolk, until well combined.

Add dry ingredients into the butter bowl and stir until well combined.

Stir in buttered pecans.

Cover the mixture with plastic wrap, pressing the plastic down onto the surface of the dough. Chill for at least 3 hours and up to 3 days.

Before baking, let dough sit at room temperature for about 30 minutes.

Preheat the oven to 350 degress F.

Line a baking sheet with parchment paper.

Roll dough into balls, about 3 tablespoons each and place 2 inches apart onto the baking sheet.

Bake on the middle rack until the edges are set and just beginning to turn golden brown, about 9-12 minutes. Remove from oven and immediately press into the center of the cookies a pecan halve.

Let rest on baking sheet for 5 minutes, then transfer to a cooling rack.

Store in an airtight container for up to 5 days.