In the bowl of a stand mixer, on medium-high speed, cream butter and sugar together, until creamy.  Stop to scrape the bottom and sides two times. This should take about 2-3 minutes.

Add in the egg yolk and beat well.

Add in flour and salt and mix on medium until the dough forms a ball.  As soon as you cannot see the flour anymore, stop mixing.  Do not over-mix.  You want the dough to remain light and fluffy.

Cover the bowl with saran wrap, and place in fridge for about an hour.  The dough needs to be cold.  (if its not cold, the cookies will cook flat)

Preheat oven to 350 degrees, roll 1 inch dough balls, and place on parchment paper lined baking sheet.  Using a fork, press down on top of dough ball gently to flatten the ball slightly.

Press a half pecan on top of the fork marks.  Bake in preheated oven for 6-8 minutes.  Note:  if you like softer cookies, about 7 minutes is correct, if you prefer crunchy and browned, 10-12 minutes would be better.

Enjoy!!