Start by preheating your oven to 350°F (175°C). This ensures your cookies bake evenly and achieve that perfect golden color.
In a medium bowl, whisk together the all-purpose flour, cornstarch, and baking soda. Set this mixture aside as you prepare the wet ingredients.
In a large mixing bowl, add the cold salted butter, white sugar, and brown sugar. Using an electric mixer, cream the mixture until it’s light and fluffy.
Crack the egg into the creamed butter and sugars, and add the vanilla extract. Mix until well combined.
Gradually add the dry ingredients to the wet mixture, stirring gently with a silicone spatula. Be careful not to overmix; it’s okay if there are a few flour streaks remaining.
Gently fold in the chopped pecans, semi-sweet chocolate chunks, and chocolate chips.
Using a cookie scoop, drop heaping tablespoons of dough onto a baking sheet lined with parchment paper.
Place the baking sheet in the preheated oven and bake for 10-12 minutes, or until the edges are golden brown but the centers look slightly underbaked.
Once out of the oven, let the cookies cool on the baking sheet for about 5 minutes before transferring them to a wire rack.
