Place 8 tablespoons of butter (1 stick) in a small pan and heat over medium heat until melted.

Cook the butter for approximately 5 minutes until it turns light brown, stirring occasionally.

Add the browned butter to a large mixing bowl, making sure to include any browned bits from the bottom of the pan.

Melt the remaining 4 tablespoons (1/2 stick) of butter and add it to the mixing bowl with the browned butter.

Add the brown sugar to the mixing bowl and beat with an electric mixer or whisk until combined.

Mix in the egg and vanilla extract until well combined.

In a separate small bowl, combine the flour and baking soda, then add them to the wet ingredients in the mixing bowl.

Mix until just barely combined, ensuring that large lumps of flour are incorporated into the dough.

Gently stir in the chopped pecans until evenly distributed throughout the dough. Be careful not to over-mix.

Place the bowl of dough in the refrigerator for 30 minutes to chill.

Preheat the oven to 375°F (190°C) while the dough is chilling.

After chilling, scoop out 1 ½ - 2 tablespoons of dough and roll them into balls. Place the dough balls on a parchment-lined baking sheet, spacing them about 2 inches apart.

Press down each ball slightly so it's no thicker than ½ inch.

Bake for 12-14 minutes, until the cookies are lightly golden brown.

Allow the cookies to cool on the baking sheet for 10 minutes before transferring them to a wire rack to cool completely.