In a 300°F oven, toast the chopped pecans on a large parchment paper or silicone mat-lined baking sheet for 15 minutes. Stir twice during this time. Turn oven off and set pecans aside.

In a large bowl using a hand-held mixer or stand mixer fitted with a paddle attachment, beat the butter for 1 minute on medium speed until totally smooth and creamy. Add the granulated sugar and brown sugar and beat on medium high speed until fluffy and light in color. Beat in eggs and vanilla on high speed. Scrape down the sides and bottom of the bowl as needed.

In a separate bowl, whisk the flour, cornstarch, baking soda, and salt together until combined. On low speed, slowly mix into the wet ingredients until combined. The cookie dough will be quite thick. Add the toasted chopped pecans, mix on low for about 5 to 10 seconds until evenly distributed. Cover dough tightly with aluminum foil or plastic wrap and chill for at least 3 hours and up to 3 days. Chilling is compulsory for this cookie dough.

Remove cookie dough from the fridge and permit to sit at room temperature for 20 minutes. If the cookie dough chilled longer than 3 hours, let it sit at room temperature for about 30 minutes. This makes the cookie dough easier to scoop and roll. The dough can be chilled over night.

Preheat oven to 350°F. Line two large baking sheets with parchment paper or silicone baking mats. Set aside.

Once chilled, the dough might be barely crumbly, but will come together if you work the dough with your hands as you roll into individual balls. Scoop and roll balls of dough, about 1 tablespoon of dough each, into balls. You may roll the cookie dough balls into the 1/3 cup of granulated sugar if you would like. It’s optional because I merely did this for looks, the sugar gives them a pretty sparkle. Or you can bake the cookies without the sugar rolling and sprinkle with a little sea salt when they come out of the oven.

Bake the cookies for 10 minutes for chewy texture or 11 minutes for crispier cookies, until barely golden brown around the edges. Rotate the pan once during bake time to avoid hot spots in your oven. The baked cookies will look extremely soft in the centers when you remove them from the oven. Allow to cool for 5 minutes on the cookie sheet. If the cookies are too puffy, try gently pressing down on them with the back of a spoon. They will barely deflate as you let them cool. Transfer to cooling rack to cool totally.

Cookies stay fresh covered at room temperature for up to 1 week. Baked cookies freeze well, up to 3 months. Unbaked cookie dough balls freeze well, up to 3 months. Bake frozen cookie dough balls for an additional minute, no need to thaw.