In a medium skillet over medium heat, melt 3 tablespoons of unsalted butter. Add the chopped pecans and toast them gently for about 3-5 minutes until fragrant and golden. Remove from heat and cool.

In a saucepan, melt 2 sticks of unsalted butter over medium heat, stirring continuously for 5-7 minutes until a rich golden brown and nutty aroma develops. Cool slightly.

In a mixing bowl, whisk together 2 cups of all-purpose flour, 1 tablespoon of cornstarch, 1 teaspoon of salt, 1 teaspoon of ground cinnamon, and 1 teaspoon of baking soda. Set aside.

In a large mixing bowl, combine cooled browned butter, 1 cup of dark brown sugar, ½ cup of granulated sugar, 1 tablespoon of vanilla extract, and 2 large eggs. Whisk until smooth and creamy.

Gradually add dry ingredients to wet mixture, folding gently with a spatula until just combined; avoid overmixing.

Fold in the cooled, browned pecans until evenly distributed throughout the dough.

Cover dough with plastic wrap and refrigerate for 1-2 hours or up to 24 hours.

Preheat oven to 375°F (190°C). Line baking sheet with parchment paper. Use a cookie scoop to place balls of dough onto the sheet, 2 inches apart. Bake for 9-12 minutes until edges are lightly golden.

Remove cookies from oven, let cool on baking sheet for 5 minutes, then transfer to a wire rack. Optionally, decorate with an extra pecan half while cooling.