Make sure to preheat your oven to 350º and cover 2 baking sheets with parchment paper.
Next, beat the butter, granulated sugar and brown sugar with an electric mixer until the mixture is light and creamy.
Then add the eggs, vanilla extract and beat again for another 2 minutes. Immediately add the flour, baking soda, salt and mix until well blended.
When finished, place the balls, using a medium cookie spoon, on the prepared baking sheets and add half a pecan on top of each cookie. Bake until golden brown, about 10 to 15 minutes. Finally, cool the cookies on a wire rack.