Preheat the oven to 350℉/176℃. Prep the baking trays by lining them with parchment paper and set aside. Melt the butter and set aside to cool for at least 10 minutes while you prep the rest of your ingredients.

In a medium-sized bowl, add in flour, baking soda, baking powder, cornstarch, and salt. Mix together and set aside.

In a medium pot, add the butter and melt. Then add in chopped pecans and mix for 3-4 minutes on medium-high heat until toasted. Set aside to cool and for later.

In a large bowl, add in melted and cooled butter, brown sugar, and white sugar. Whisk until well combined.

Add in eggs and vanilla and continue whisking, scraping the bowl as needed.

Add in the dry ingredients and using a spatula, gently fold until a sticky cookie batter forms.

Add in the cooled toasted pecans and keep mixing. Don't over-mix!

Place into the fridge for minimum 1 hour (You can also make before-hand and chill overnight!).

Once chilled, scoop 6 cookies per baking tray (about 2 tbsp per cookie) spaced 2-3 inches apart. Add a pecan or two on top of each cookie. (Keep the remaining dough that still has to bake in the fridge as you are baking).

Bake for 13-16 minutes or until the edges are a golden brown and the middle is slightly puffy and underbaked. Allow the cookies to sit on the baking tray after baking as they continue to bake from the hot pan for 5-10 minutes.

Transfer to a cooling rack to cool completely and enjoy!